SILICON DIOXIDE

Silicon dioxide = Silica

CAS Number: 7631-86-9     
EC Number: 231-545-4
E number: E551 (acidity regulators, ...)
Chemical formula: SiO2
Molar mass: 60.08 g/mol

Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO2, most commonly found in nature as quartz and in various living organisms.
In many parts of the world, silica is the major constituent of sand. 
Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as a synthetic product. 
Notable examples include fused quartz, fumed silica, silica gel, and aerogels. 
Silicon dioxide is used in structural materials, microelectronics (as an electrical insulator), and as components in the food and pharmaceutical industries.

Silicon Dioxide is a highly insoluble thermally stable Silicon source suitable for glass, optic and ceramic applications. 
Oxide compounds are not conductive to electricity. 
However, certain perovskite structured oxides are electronically conductive finding application in the cathode of solid oxide fuel cells and oxygen generation systems. 
They are compounds containing at least one oxygen High Purity (99.999%) Silicon Oxide (SiO2)Powderanion and one metallic cation. 
They are typically insoluble in aqueous solutions (water) and extremely stable making them useful in ceramic structures as simple as producing clay bowls to advanced electronics and in light weight structural components in aerospace and electrochemical applications such as fuel cells in which they exhibit ionic conductivity. 
Metal oxide compounds are basic anhydrides and can therefore react with acids and with strong reducing agents in redox reactions. 
Silicon Oxide is also available in pellets, pieces, powder, sputtering targets, tablets, and nanopowder (from American Elements' nanoscale production facilities). 
Silicon Dioxide is generally immediately available in most volumes. 
Ultra high purity, high purity, submicron and nanopowder forms may be considered. 
American Elements produces to many standard grades when applicable, including Mil Spec (military grade); ACS, Reagent and Technical Grade; Food, Agricultural and Pharmaceutical Grade; Optical Grade, USP and EP/BP (European Pharmacopoeia/British Pharmacopoeia) and follows applicable ASTM testing standards. 
Typical and custom packaging is available. 
Additional technical, research and safety (MSDS) information is available as is a Reference Calculator for converting relevant units of measurement.

Silicon dioxide Uses
Structural use
About 95% of the commercial use of silicon dioxide (sand) occurs in the construction industry, e.g. for the production of concrete (Portland cement concrete).
Certain deposits of silica sand, with desirable particle size and shape and desirable clay and other mineral content, were important for sand casting of metallic products.
The high melting point of silica enables it to be used in such applications such as iron casting; modern sand casting sometimes uses other minerals for other reasons.
Crystalline silica is used in hydraulic fracturing of formations which contain tight oil and shale gas.

The primary use of silicon dioxide is in the building industry. 
Silicon dioxide is used to make ceramics, enamels, concrete, and specialized silica bricks used as refractory materials. 
Silicon dioxide is also one of the raw materials from which all kinds of glass are made. 
Vitreous silicon dioxide is an important constituent of specialized types of glass, such as that used in making laboratory equipment, mirrors, windows, prisms, cells, and other kinds of optical devices. 
Silicon dioxide is also used as an anti-caking or thickening agent in a variety of foods and pharmaceutical products. 
Some other applications of silicon dioxide include:
-In the manufacture of polishing and grinding materials;
-As molds for casting;
-In the production of elemental silicon;
-As a filler in many different kinds of products, including paper, insecticides, rubber products, pharmaceuticals, and cosmetics;
-As an additive in paints to produce a low-gloss finish;
-In the reinforcement of certain types of plastics.

The primary application of silica gel is as a drying agent. 
Packets of silica gel are found in many consumer products, such as electronic equipment, hardware tools, clothing, CD and DVD discs, and foodstuffs. 
Because of Silicon dioxides ability to adsorb moisture from the surrounding air, silica gel prevents rust and other forms of oxidation. 
Silica gel also has similar applications in industry. 
For example, Silicon dioxide is used to dry compressed air, air conditioning systems, and natural gas. 
The compound is also used to bleach petroleum oils and as an anti-caking agent for cosmetics and pharmaceuticals.

Why is silicon dioxide used in food additives?
Manufacturers use silica to make everything from glass to cement, but it also has a use in the food industry as an additive and anticaking agent. 
This type of food additive prevents foods from caking or sticking together in clumps. 
This may help ensure a product’s shelf life, protect against the effects of moisture, and keep powdered ingredients from sticking together and helping them flow smoothly.

Precursor to glass and silicon
Silica is the primary ingredient in the production of most glass. 
As other minerals are melted with silica, the principle of Freezing Point Depression lowers the melting point of the mixture and increases fluidity. 
The glass transition temperature of pure SiO2 is about 1475 K.
When molten silicon dioxide SiO2 is rapidly cooled, it does not crystallize, but solidifies as a glass. 
Because of this, most ceramic glazes have silica as the main ingredient.
The structural geometry of silicon and oxygen in glass is similar to that in quartz and most other crystalline forms of silicon and oxygen with silicon surrounded by regular tetrahedra of oxygen centers. 
The difference between the glass and crystalline forms arises from the connectivity of the tetrahedral units: Although there is no long range periodicity in the glassy network ordering remains at length scales well beyond the SiO bond length. 
One example of this ordering is the preference to form rings of 6-tetrahedra.
The majority of optical fibers for telecommunication are also made from silica. 
Silicon dioxide is a primary raw material for many ceramics such as earthenware, stoneware, and porcelain.
Silicon dioxide is used to produce elemental silicon. 
The process involves carbothermic reduction in an electric arc furnace:
SiO2 + 2 C -> Si + 2 CO

Fumed silica
Fumed silica, also known as pyrogenic silica, is prepared by burning SiCl4 in an oxygen-rich hydrogen flame to produce a "smoke" of SiO2.
SiCl4 + 2 H2 + O2 -> SiO2 + 4 HCl
Silicon dioxide can also be produced by vaporizing quartz sand in a 3000 °C electric arc. 
Both processes result in microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary particles which then agglomerate into tertiary particles, a white powder with extremely low bulk density (0.03-.15 g/cm3) and thus high surface area.
The particles act as a thixotropic thickening agent, or as an anti-caking agent, and can be treated to make them hydrophilic or hydrophobic for either water or organic liquid applications

Silica fume is an ultrafine powder collected as a by-product of the silicon and ferrosilicon alloy production. 
Silicon dioxide consists of amorphous (non-crystalline) spherical particles with an average particle diameter of 150 nm, without the branching of the pyrogenic product. 
The main use is as pozzolanic material for high performance concrete.

Food, cosmetic, and pharmaceutical applications
Silica, either colloidal, precipitated, or pyrogenic fumed, is a common additive in food production. 
Silicon dioxide is used primarily as a flow or anti-caking agent in powdered foods such as spices and non-dairy coffee creamer, or powders to be formed into pharmaceutical tablets.
Silicon dioxide can adsorb water in hygroscopic applications. 
Colloidal silica is used as a fining agent for wine, beer, and juice, with the E number reference E551.

In cosmetics, silica is useful for its light-diffusing properties and natural absorbency.
Diatomaceous earth, a mined product, has been used in food and cosmetics for centuries. 
Silicon dioxide consists of the silica shells of microscopic diatoms; in a less processed form it was sold as "tooth powder".
Manufactured or mined hydrated silica is used as the hard abrasive in toothpaste.

SiO2 Uses (Silicon Dioxide)
Silicon Dioxide is used in the construction industry to produce concrete.
In Silicon dioxides crystalline form it is used in hydraulic fracturing.
Silicon dioxide is used in the production of glass.
Silicon dioxide is used as a Sedative.
Silicon dioxide is used in the production of produce elemental silicon.
Silicon dioxide is used as anti-caking agent in powdered foods like spices.
Silicon dioxide is used as a fining agent in juice, beer, and wine.
Silicon dioxide is used pharmaceutical tablets.
Silicon dioxide is used in toothpaste to remove tooth plaque.

Semiconductors
See also: Surface passivation, Thermal oxidation, Planar process, and MOSFET
Silicon dioxide is widely used in the semiconductor technology for the primary passivation (directly on the semiconductor surface), as an original gate dielectric in MOS technology. 
Today when scaling (dimension of the gate length of the MOS transistor) has progressed below 10 nm silicon dioxide has been replaced by other dielectric materials like hafnium oxide or similar with higher dielectric constant compared to silicon dioxide, as a dielectric layer between metal (wiring) layers (sometimes up to 8-10) connecting elements to each other and as a secondary passivation layer (for protecting semiconductor elements and the metallization layers) typically today layered with some other dielectrics like silicon nitride. 
Because silicon dioxide is a native oxide of silicon it is more widely used compared to other semiconductors like Gallium arsenide or Indium phosphide.
Silicon dioxide could be grown on a silicon semiconductor surface.
Silicon oxide layers could protect silicon surfaces during diffusion processes, and could be used for diffusion masking.

Surface passivation is the process by which a semiconductor surface is rendered inert, and does not change semiconductor properties as a result of interaction with air or other materials in contact with the surface or edge of the crystal.
The formation of a thermally grown silicon dioxide layer greatly reduces the concentration of electronic states at the silicon surface.
SiO2 films preserve the electrical characteristics of p–n junctions and prevent these electrical characteristics from deteriorating by the gaseous ambient environment.
Silicon oxide layers could be used to electrically stabilize silicon surfaces.
The surface passivation process is an important method of semiconductor device fabrication that involves coating a silicon wafer with an insulating layer of silicon oxide so that electricity could reliably penetrate to the conducting silicon below. 
Growing a layer of silicon dioxide on top of a silicon wafer enables it to overcome the surface states that otherwise prevent electricity from reaching the semiconducting layer.
The process of silicon surface passivation by thermal oxidation (silicon dioxide) is critical to the semiconductor industry. 
Silicon dioxide is commonly used to manufacture metal-oxide-semiconductor field-effect transistors (MOSFETs) and silicon integrated circuit chips (with the planar process).

Other
Hydrophobic silica is used as a defoamer component.
In Silicon dioxides capacity as a refractory, Silicon dioxide is useful in fiber form as a high-temperature thermal protection fabric.
Silica is used in the extraction of DNA and RNA due to its ability to bind to the nucleic acids under the presence of chaotropes.
Silica aerogel was used in the Stardust spacecraft to collect extraterrestrial particles.
Pure silica (silicon dioxide), when cooled as fused quartz into a glass with no true melting point, can be used as a glass fiber for fiberglass.

Water solubility
The solubility of silicon dioxide in water strongly depends on its crystalline form and is three-four times higher for silica than quartz; as a function of temperature, it peaks around 340 °C.
This property is used to grow single crystals of quartz in a hydrothermal process where natural quartz is dissolved in superheated water in a pressure vessel that is cooler at the top. 
Crystals of 0.5–1  kg can be grown over a period of 1–2 months.
These crystals are a source of very pure quartz for use in electronic applications.

What is it?
Silicon dioxide (SiO2), also known as silica, is a natural compound made of two of the earth’s most abundant materials: silicon (Si) and oxygen (O2).
Silicon dioxide is most often recognized in the form of quartz. 
Silicon dioxide’s found naturally in water, plants, animals, and the earth. 
The earth’s crust is 59 percent silica. 
Silicon dioxide makes up more than 95 percent of known rocks on the planet. 
When you sit on a beach, Silicon dioxide’s silicon dioxide in the form of sand that gets between your toes.
Silicon dioxide’s even found naturally in the tissues of the human body. 
Though Silicon dioxide’s unclear what role it plays, Silicon dioxide’s thought to be an essential nutrient our bodies need.

Why is Silicon dioxide in food and supplements?
Silicon dioxide is found naturally in many plants, such as:
-leafy green vegetables
-beets
-bell peppers
-brown rice
-oats
-alfalfa
Silicon dioxide is also added to many foods and supplements.
As a food additive, Silicon dioxide serves as an anticaking agent to avoid clumping. 
In supplements, Silicon dioxide’s used to prevent the various powdered ingredients from sticking together.

Silica, SiO2, is a white or colorless crystalline compound found mainly as quartz, sand, flint, and many other minerals. 
Silica is an important ingredient to manufacture a wide variety of materials.
Quartz; Quartz is the most abundant silica mineral. 
Pure Quartz is colorless and transparent. 
Silicon dioxide occurs in most igneous and practically all metamorphic and sedimentary rocks. 
Silicon dioxide is used as a component of numerous industrial materials.
Silicon (Si) has the atomic number 14 and is closely related to carbon. 
Silicon dioxide is a relatively inert metalloid.

Silicon is often used for microchips, glass, cement, and pottery.
Silica is the most abundant mineral found in the crust of the earth. 
One of the most common uses of silica quarts is the manufacturer of glass.
Silica is the fourteenth element on the periodic table. 
Silicon dioxide can sometimes be found as the substance, quartz which is usually used in jewelry, test tubes, and when placed under pressure, generates an electrical charge.
Quartz is the second most abundant mineral in the Earth's crust. 
Silicon dioxide is a clear, glossy mineral with a hardness of 7 on the MOHS scale.
Silica, Sa,is a component of glass and concrete. 
A form of Silica commonly known as quartz, Silica tetrahedra, is the second most common mineral in the earth's crust, it comes in many different forms.

Silica is a compound of silicon and oxygen. 
Earth's outer crust contains 59% of this material. 
Silicon dioxide has three major rock forms, which are quartz, tridymite, and cristobalite.
Silica, commonly known in the form of quartz, is the dioxide form of silicon, SiO2. 
Silicon dioxide is usually used to manufacture glass, ceramics and abrasives.
Quartz is the second most common mineral in Earth’s crust. 
Silicon dioxides chemical name is SiO2. 

Although quartz is common, Silicon dioxide is usually twinned so industries often Silica; Also known as the silicon dioxide, has a white powdery substance solid. 
Silicon dioxide is used in production in many products such as glass, food additive and raw material for production.
The chemical compound silica, also known as silicon dioxide, is known for its hardness since the 16th century. 
Silicon dioxide is found in nature in many different forms, such as flint, quartz, and opal.
Silica (quartz): Silica, SiO2, is a chemical compound that is composed of one silicon atom and two oxygen atoms. 
Silicon dioxide appears naturally in several crystalline forms, one of which is quartz.
Silica Quartz- A colorless, ordorless crystal found in different colors such as white, green, black, purple. 

Silicon dioxide will not burn to the touch but can cause cancer Silicon dioxide, commonly known as silica (and/or quartz), is a prevalent element in the Earth's crust. 
One fourth, or twenty-eight percent (to be percise) of the Earth's crust is composed of silica.
Silica:scientific name for a group of minerals composed of silicon and oxygen atoms, (crystalline silica). 
Different soils contain all forms of crystalline silica in the form of quartz.
Quartz silica is a colorless/white, black, purple, or green crystals. 
Silicon dioxide has no odor and will not burn. 
Silicon dioxide's cancer hazardous. 
Silicon dioxide is found in mines and tunnels.
Silica, or silicon dioxide, is the oxide of silicon. 
Silicon dioxide is found in nature in several forms; one of which is quartz. 
Quartz is the second most common mineral on Earth.

Silica(quartz); Silica(quartz) is a colorless crystal like beryl. 
The silica(quartz) come in different colors, such as yellow(citrine), smoky, and purple(amethyst). 
The color changes because of transition-metal impurities.
Silica, a white to colorless crystalline compound, is usually in the form of quartz. 
Silicon dioxide is used as building stones and to make glass. 
Silica has covalent bonding and forms a network structure.
Silica, SiO2, has a crystalline form called quartz, which is found in many types of rocks, and is the second most abundant mineral in the Earth’s crust. 
This very hard mineral is usually colorless.

Silica (quartz): The second most common element in the earth's crust, silica is never found in its natural state, and alloys with a number of different metals.
Silica, SiO2, has a crystalline form called quartz, which is found in numerous types of rocks, and is the second most plentiful mineral in the Earth’s crust. 
This very firm mineral is usually colorless Silicon dioxide exists naturally within the earth and our bodies. 
There isn’t yet evidence to suggest it’s dangerous to ingest as a food additive, but more research is needed on what role it plays in the body. 
Chronic inhalation of silica dust can lead to lung disease.
People who have serious allergies have a vested interest in knowing what additives are in the foods they eat. 
But even if you don’t have such allergies, it’s best to be cautious with food additives. 
And even minor changes in levels of minerals can have a profound effect on healthy functioning. 
A good approach is to eat whole foods and get healthy levels of silicon dioxide.
As with many food additives, consumers often have concerns about silicon dioxide as an additive. 
However, numerous studies suggest there’s no cause for these concerns.

What does the research say?
The fact that silicon dioxide is found in plants and drinking water suggests it’s safe. 
Research has shown that the silica we consume through our diets doesn’t accumulate in our bodies. 
Instead, Silicon dioxide’s flushed out by our kidneys.
However, the progressive, often fatal lung disease silicosis can occur from chronic inhalation of silica dust.
This exposure and disease primarily occurs among people who work in:
-mining
-construction
-quarrying
-the steel industry
-sandblasting

In the majority of silicates, the silicon atom shows tetrahedral coordination, with four oxygen atoms surrounding a central Si atom (see 3-D Unit Cell). 
Thus, SiO2 forms 3 dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. 
In contrast, CO2 is a linear molecule. 
The starkly different structures of the dioxides of carbon and silicon is a manifestation of the Double bond rule.
SiO2 has a number of distinct crystalline forms, but they almost always have the same local structure around Si and O. 
In α-quartz the Si-O bond length is 161 pm, whereas in α-tridymite it is in the range 154–171 pm. 
The Si-O-Si angle also varies between a low value of 140° in α-tridymite, up to 180° in β-tridymite. 
In α-quartz, the Si-O-Si angle is 144°.

Polymorphism
Alpha quartz is the stable form of solid SiO2 at room temperature. 
The high-temperature minerals, cristobalite and tridymite, have both lower densities and indices of refraction than quartz. 
The transformation from α-quartz to beta-quartz takes place abruptly at 573 °C. 
Since the transformation is accompanied by a significant change in volume, it can easily induce fracturing of ceramics or rocks passing through this temperature limit.
The high-pressure minerals, seifertite, stishovite, and coesite, though, have higher densities and indices of refraction than quartz.
Stishovite has a rutile-like structure where silicon is 6-coordinate. 
The density of stishovite is 4.287 g/cm3, which compares to α-quartz, the densest of the low-pressure forms, which has a density of 2.648 g/cm3.
The difference in density can be ascribed to the increase in coordination as the six shortest Si-O bond lengths in stishovite (four Si-O bond lengths of 176 pm and two others of 181 pm) are greater than the Si-O bond length (161 pm) in α-quartz.
The change in the coordination increases the ionicity of the Si-O bond.
More importantly, any deviations from these standard parameters constitute microstructural differences or variations, which represent an approach to an amorphous, vitreous, or glassy solid.

Faujasite silica, another polymorph, is obtained by dealumination of a low-sodium, ultra-stable Y zeolite with combined acid and thermal treatment. 
The resulting product contains over 99% silica, and has high crystallinity and surface area (over 800 m2/g). 
Faujasite-silica has very high thermal and acid stability. 
For example, it maintains a high degree of long-range molecular order or crystallinity even after boiling in concentrated hydrochloric acid.

Molten SiO2
Molten silica exhibits several peculiar physical characteristics that are similar to those observed in liquid water: negative temperature expansion, density maximum at temperatures ~5000 °C, and a heat capacity minimum.
Silicon dioxides density decreases from 2.08 g/cm3 at 1950 °C to 2.03 g/cm3 at 2200 °C.

Molecular SiO2
Molecular SiO2 is linear structure. 
Silicon dioxide has been produced by combining silicon monoxide with oxygen atoms in an argon matrix. 
Dimeric silicon dioxide, (SiO2)2 has been generated by reacting O2 with matrix isolated dimeric silicon monoxide, (Si2O2). 
In dimeric silicon dioxide there are two oxygen atoms bridging between the silicon atoms with an Si-O-Si angle of 94° and bond length of 164.6 pm and the terminal Si-O bond length is 150.2 pm. 
The Si-O bond length is 148.3 pm, which compares with the length of 161 pm in α-quartz. 
The bond energy is estimated at 621.7 kJ/mol.

Synonyms:
Quartz, Silica, Cristobalite, Sand

Natural occurrence
Geology
SiO2 is most commonly found in nature as quartz, which comprises more than 10% by mass of the earth's crust.
Quartz is the only polymorph of silica stable at the Earth's surface. 
Metastable occurrences of the high-pressure forms coesite and stishovite have been found around impact structures and associated with eclogites formed during ultra-high-pressure metamorphism. 
The high-temperature forms of tridymite and cristobalite are known from silica-rich volcanic rocks. 
In many parts of the world, silica is the major constituent of sand.

IUPAC name
Silicon dioxide

What is silicon dioxide?
Silicon dioxide, or silica, is a combination of silicon and oxygen, two very abundant, naturally occurring materials.
There are many forms of silica. 
They all have the same makeup but may have a different name, depending on how the particles arrange themselves. 
In general, there are two groups of silica: crystalline silica and amorphous silica.

Silicon dioxide occurs widely in nature. 
The Agency for Toxic Substances and Disease Registry (ATSDR) give an idea to just how common this compound is.
Silicon dioxide is easiest to recognize by its common name, quartz, which makes up about 12% of the earth’s crust. 
However, silicon dioxide also occurs naturally in everything from water and plants to animals.
Silica sand covers many beaches, and it makes up most of the rocks on earth. 
In fact, silica-containing minerals or silica itself make up more than 95% of the earth’s crust.
Silicon dioxide also exists in numerous plants that humans regularly consume, such as:
-dark, leafy greens
-some grains and cereals, such as oats and brown rice
-vegetables, such as beets and bell peppers
-alfalfa
Silicon dioxide also occurs naturally in the human body, though it is still unclear the exact role it plays.

Other names
Quartz
Silica
Silicic oxide
Silicon(IV) oxide
Crystalline silica
Pure Silica
Silicea
Silica sand

Silicon dioxide is a natural chemical mix of silicon and oxygen that has uses in many food products as an anticaking agent. 
Silicon dioxide is generally safe as a food additive, though some agencies are calling for stricter guidelines about the quality and characteristics of the silicon dioxide found in foods.

Biology
Even though it is poorly soluble, silica occurs in many plants. 
Plant materials with high silica phytolith content appear to be of importance to grazing animals, from chewing insects to ungulates. 
Silica accelerates tooth wear, and high levels of silica in plants frequently eaten by herbivores may have developed as a defense mechanism against predation.
Silica is also the primary component of rice husk ash, which is used, for example, in filtration and cement manufacturing.
For well over a billion years, silicification in and by cells has been common in the biological world. 
In the modern world it occurs in bacteria, single-celled organisms, plants, and animals (invertebrates and vertebrates). 

Prominent examples include:
Tests or frustules (i.e. shells) of diatoms, Radiolaria, and testate amoebae.
Silica phytoliths in the cells of many plants, including Equisetaceae, practically all grasses, and a wide range of dicotyledons.
The spicules forming the skeleton of many sponges.
Crystalline minerals formed in the physiological environment often show exceptional physical properties (e.g., strength, hardness, fracture toughness) and tend to form hierarchical structures that exhibit microstructural order over a range of scales. 
The minerals are crystallized from an environment that is undersaturated with respect to silicon, and under conditions of neutral pH and low temperature (0–40 °C).

Silicon dioxide is unclear in what ways silica is important in the nutrition of animals. 
This field of research is challenging because silica is ubiquitous and in most circumstances dissolves in trace quantities only. 
All the same it certainly does occur in the living body, creating the challenge of creating silica-free controls for purposes of research. 
This makes it difficult to be sure when the silica present has had operative beneficial effects, and when its presence is coincidental, or even harmful. 
The current consensus is that it certainly seems important in the growth, strength, and management of many connective tissues. 
This is true not only for hard connective tissues such as bone and tooth but possibly in the biochemistry of the subcellular enzyme-containing structures as well.

SiO2 is an oxide of silicon with a chemical name Silicon Dioxide. 
Silicon dioxide is also called Silica or Kalii bromidum or Silicic oxide or silicic acid. 
Silicon dioxide is widely found in nature as quartz.
Silicon dioxide is obtained as a transparent to grey, in its crystalline or amorphous powdered form. 
Silicon dioxide is odourless and tasteless compound.

CAS Number: 7631-86-9     
CHEBI:30563 
ChemSpider: 22683 
ECHA InfoCard: 100.028.678 
EC Number: 231-545-4
E number: E551 (acidity regulators, ...)
Gmelin Reference: 200274
KEGG: C16459 
MeSH: Silicon+dioxide
PubChem CID: 24261
RTECS number: VV7565000
UNII: ETJ7Z6XBU4 
CompTox Dashboard (EPA): DTXSID1029677

While many of the studies Trusted Source on silica have been done on animals, researchers have found no link between the food additive silicon dioxide and increased risk of cancer, organ damage, or death. 
In addition, studiesTrusted Source have found no evidence that silicon dioxide as an additive in food can affect reproductive health, birth weight, or bodyweight.
The U.S. Food and Drug Administration (FDA) has also recognized silicon dioxide as a safe food additive. 
In 2018, the European Food Safety Authority urged the European Union to impose stricter guidelines on silicon dioxide until further research could be done. 
Their concerns focused on the nano-sized particles (some of which were smaller than 100 nm).
Previously guidelines followed a 1974 paper prepared in association with the World Health Organization. 
This paper found the only negative health effects related to silicon dioxide have been caused by silicon deficiency. 
More current research may be changing the guidelines and recommendations.

Chemical formula: SiO2
Molar mass: 60.08 g/mol
Appearance: Transparent solid (Amorphous) White/Whitish Yellow (Powder/Sand)
Density: 2.648 (α-quartz), 2.196 (amorphous) g·cm−3 
Melting point: 1,713 °C (3,115 °F; 1,986 K) (amorphous) (p4.88) to
Boiling point: 2,950 °C (5,340 °F; 3,220 K) 
Magnetic susceptibility (χ): −29.6·10−6 cm3/mol

Silicon dioxide (silica, SiO2, SAS) and titanium dioxide (TiO2) are produced in high volumes and applied in many consumer and food products. 
As a consequence, there is a potential human exposure and subsequent systemic uptake of these particles. 
In this study we show the characterization and quantification of both total silicon (Si) and titanium (Ti), and particulate SiO2 and TiO2 in postmortem tissue samples from 15 deceased persons. 
Included tissues are liver, spleen, kidney and the intestinal tissues jejunum and ileum. 
Low-level analysis was enabled by the use of fully validated sample digestion methods combined with (single particle) inductively coupled plasma high resolution mass spectrometry techniques (spICP-HRMS). 
The results show a total-Si concentration ranging from <2 to 191 mg Si/kg (median values of 5.8 (liver), 9.5 (spleen), 7.7 (kidney), 6.8 (jejunum), 7.6 (ileum) mg Si/kg) while the particulate SiO2 ranged from <0.2 to 25 mg Si/kg (median values of 0.4 (liver), 1.0 (spleen), 0.4 (kidney), 0.7 (jejunum, 0.6 (ileum) mg Si/kg), explaining about 10% of the total-Si concentration. 
Particle sizes ranged from 150 to 850 nm with a mode of 270 nm. 
For total-Ti the results show concentrations ranging from <0.01 to 2.0 mg Ti/kg (median values of 0.02 (liver), 0.04 (spleen), 0.05 (kidney), 0.13 (jejunum), 0.26 (ileum) mg Ti/kg) while particulate TiO2 concentrations ranged from 0.01 to 1.8 mg Ti/kg (median values of 0.02 (liver), 0.02 (spleen), 0.03 (kidney), 0.08 (jejunum), 0.25 (ileum) mg Ti/kg). 
In general, the particulate TiO2 explained 80% of the total-Ti concentration. 
This indicates that most Ti in these organ tissues is particulate material. 
The detected particles comprise primary particles, aggregates and agglomerates, and were in the range of 50–500 nm with a mode in the range of 100–160 nm. 
About 17% of the detected TiO2 particles had a size <100 nm. 
The presence of SiO2 and TiO2 particles in liver tissue was confirmed by scanning electron microscopy with energy dispersive X-ray spectrometry.

SILICON DIOXIDE
Silica
Quartz
7631-86-9
Cristobalite
Dioxosilane
Diatomaceous earth
Silica gel
Tridymite
Sand
Infusorial earth
Silicic anhydride
KIESELGUHR
Aerosil
112945-52-5
Crystalline silica
14808-60-7
Diatomaceous silica

Silicon Dioxide: What Is Silicon dioxide? What’s Silicon dioxide Good For? And Do We Need It?
Ever wondered what that small packet you find in food or supplement bottles is? 
You know, the one that says, “Do Not Eat” even though it’s found with your food? Well, that’s called a desiccant. 
Silicon dioxides primary purpose is to absorb excess moisture so fine food particles don’t clump together (the way sugar does).
Silicon dioxides active ingredient? Silicon dioxide, more commonly known as silica, but what is silicon dioxide? 
Let’s delve into this and other questions.

What is Silicon Dioxide?
Chemically, silicon dioxide is a type of quartz, the fusion of the elements silicon (Si) and oxygen (O). 
Silicon dioxide is one of the more abundant substances on Earth, making up 59 percent of the crust. 
If you’ve been to the beach before, then you will have seen silica. 
Silicon dioxide’s just that Silicon dioxide has a different name there: sand
And even though it’s a “rock,” you’ll be surprised to know that silica is also found in organisms, too.
Plants, animals and, yes even us, have trace amounts of it. 
Chances are you’ve eaten Silicon dioxide regularly since everything from vegetables to oats have it.

Dicalite
Wessalon
Glass
Ludox
Nyacol
Zorbax sil
Silica, amorphous
Cab-O-sil
Christensenite
Crystoballite
Silicon(IV) oxide
61790-53-2
Siliceous earth
Amorphous silica
QUARTZ (SIO2)
112926-00-8
Silica, colloidal
60676-86-0
Chalcedony
Diatomite
Agate

Silicon dioxide, also known as silica, is a chemical compound commonly used in food as an anti-caking agent or in cosmetics to prevent corrosion, according to the USDA. 
Silicon dioxide helps keep the powders free-flowing and moisture-free and is a common additive in foods like flour, baking powder, sugar and salt, according to the Food and Drug Administration (FDA).
While silicon dioxide is safe for consumption, it can be unnerving to hear that you may be eating the same additive used in your makeup. 
However, this compound is totally safe to use, according to the USDA. 
Without silicon dioxide, many of the foods you buy would begin to lump and clot due to moisture absorption.

Silica is a chemical compound also known as silicon dioxide or silox. 
The chemical formula for silicon is SiO2. 
Silica may be found in many forms of nature. 
For example, flint, quartz, and opal.
Silica is also known as silicon dioxide SiO2. 
Silica has three main crystalline varieties: quartz the most abundant, tridymite, and cristobalite. 
The mass of the earths crust is 59 percent Silica.
Quartz is mainly made up of silica. 

The formula for it is SiO2. 
Silicon dioxide has a hardness of 7 on the Mohs scale. 
Silicon dioxide has the density of 2.65g/cm3 Silica, SiO2, is composed of Silicone and Oxygen. 
Silicon dioxide has been known since ancient times, is found in sand, and is a major component of glass.
Silica is a chemical compound, also called silicon dioxide. 
Silicon dioxide can sometimes be found as the substance, quartz which is usually used in jewelry, test tubes, and when placed under pressure, generates an electrical charge.
Silica is also known as silicon dioxide, the chemical compound is oxide of silicon and the chemical formula is SiO2. 
Silicon dioxide’s principle component in most types of glass and substances such as concrete.
Silica (quartz); is a naturally occurring minerals that can be found in mines and use in the fabrication of stone and clay products. 
Silica is odorless and various in color.

Silica – comes from silicone after it oxidizes. 
Silicon dioxide helps form most hard things like glass, porcelain, and some concrete. 
Silicon dioxides found natural in flint, quarts and opal. 
Wesley hamachi Quartz, the clear and opaque mineral, is the second most common mineral in the Earth’s continental crust. 
The six-sided shape of the mineral makes it unique and elegant to observe.
Silica: Silica can be found in nature as 35 different crystalline forms. 
One of its forms is quartz; which can generate current when mechanical stress is applied to it. 
Most sand is made up of silica depending on its geographical location. 

Silica is also used to make glass.
Silica (Quartz) is chemical compound silicon dioxide SiO2. 
Silica is often found in nature as sand (non coastal), usually in the form of quartz. 
The most common form of manufactured silica is glass.
Silica, is a natural compound that has a crystal characteristic and can be found in beach sand.
The most common usage is that of glass in which Silica is fused together.

Silica; silica (quartz), the dioxide form of silicon, SiO2, used usually in the form of its prepared white powder chiefly in the manufacture of glass, water glass, ceramics, and abrasives.
Silica is the dioxide form of silicon, SiO2, and occurs mostly as quartz sand, flint, and agate. 
Silica's powder form is used to manufacture glass, ceramics, etc. 
Silica SiO2 is the chemical compound silicon dioxide. 
Silicon dioxide is formed when silicon is exposed to oxygen.
Silicon dioxide has a covalent bond and is a superior electric insulator, posessing high chemical stability.

Cab-o-sil M-5
colloidal silica
Cristobalite (SiO2)
Fused silica
Quartz glass
Quartz sand
Silica slurry
Silicone dioxide
SILICA, VITREOUS
Colloidal silicon dioxide

Linear Formula: SiO2
CAS Number: 60676-86-0
Molecular Weight: 60.08
EC Number: 262-373-8

Silicon dioxide, or silica, is an oxide of silicon with the chemical formula SiO2. 
Silicon dioxide is found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite as transparent and tasteless crystals. 
Inhalation of fine crystals is toxic to humans leading to respiratory toxicity. 
In powdered food products and pharmaceutical tablets, silicon dioxide is added as a flow agent to absorb water. 
Colloidal silica is also used as a wine, beer, and juice fining agent or stabilizer.

Siliceous earth, purified
Min-U-Sil
Silicon dioxide (amorphous)
Silicon dioxide, fumed
Siliziumdioxid
14464-46-1
UNII-ETJ7Z6XBU4
91053-39-3
Kieselsaeureanhydrid
15468-32-3
CHEBI:30563

Silicon Dioxide in Food and Supplements
"Like many other chemical terms that people think are harmful just because they're hard to pronounce, silicon dioxide sounds ominous," Bonnie Taub-Dix, RD, tells LIVESTRONG.com. 
"But Silicon dioxide actually appears naturally in many foods including leafy greens, oats, bell peppers and beets."
When Silicon dioxide comes to supplements, silica is also a common food additive found in many protein powders, according to Julie Upton, RD and co-founder of Appetite for Health. 
The compound prevents the whey and other protein powders from clumping over time.
Aside from its use in powdered foods, silica is also used as a stabilizer in the production of beer, according to the FDA. 
However, the additive is then filtered out of the alcohol in the final processing steps.

SiO2
(SiO2)n
43-63C
MFCD00011232
ETJ7Z6XBU4
Silicon dioxide, colloidal
ENT 25,550
[SiO2]
Silica, crystalline - fused
Silicagel
Silicon dioxide, amorphous gel
Silicondioxide
Silica gel desiccant, indicating
Celite
Sand, Ottawa
Sand, Sea
silica gel desiccant
MFCD00217788
Silica, mesostructured
Sillikolloid
Acticel
Aerosil 380

What Does Silicon dioxide Do?
Silicon dioxide is a common substance used in a variety of industrial applications. 
Everything from ceramics to glass use Silicon dioxide in one form or another. 
In the food industry, silica is most often used as an anti-caking agent. 
Many foodstuffs, such as sugar and flour, tend to clump together in moist conditions.
Moisture also promotes bacterial growth and can shorten a product’s shelf life. 
Silicon dioxide prevents this by absorbing excess moisture from the atmosphere. 
Silicon dioxide can be mixed straight into the food or separated into its own container, as is the case with the desiccant pack.

Is Silicon Dioxide Natural or Synthetic?
Since it’s pretty abundant, commercial silica is often derived from natural sources. 
Natural quartz is obtained from sand mining and then crushed or milled. 
Further processing may be needed to create purer or finer silica, depending on the end-use.

Amethyst
Aquafil
Carplex
Cataloid
Crysvarl
Extrusil
Flintshot
Nalcoag
Novaculite
Porasil
Santocel
Silikil
Silikill
Siloxid
Sipernat
Superfloss

Silicon dioxide is a compound that’s naturally found in the earth’s crust in a crystalline state. 
Silicon dioxide can be obtained from mining and purifying quart.
Silicon dioxide is also found in some organisms and animals, the human body (it’s a component of human ligaments, cartilage and musculature), plus some plants (especially grains) and in drinking water.
Additionally, it’s created in labs and used as a common food additive, found in things like baking ingredients, protein powders and dried spices. 
This compound has a variety of uses in industries ranging from food and cosmetics to construction and electronics.

What is silicon dioxide made of? 
Silicon dioxide’s composed of a combination of silicon (Si) and oxygen (O), which is why it has the chemical formula SiO2.

What is silica, and how is Silicon dioxide different?
Silicon dioxide goes by the common name silica. 
Silicon dioxide’s also sometimes referred to as silicic anhydride or silicate.

Silica/silicon dioxide comes in several forms, depending on how it’s manufactured, including:
Crystalline silica, which is usually obtained from mining quartz. 
Quartz actually comprises a high percentage of the Earth’s crust, so this type is widely available. 
This isn’t the form used in foods and can be problematic when inhaled over long periods of time.
Amorphous silica, found in the earth’s sediments and rocks. 
This also forms diatomite, diatom silica or diatomaceous earth, which is made from deposits that accumulate over time in the sediment of rivers, streams, lakes and oceans.
This is the type most often used as an anti-caking agent to keep powdered foods free-flowing and to prevent moisture absorption.
Colloidal silicon dioxide, which is used in tablet-making. 
This type is found in supplements because it has anti-caking, adsorbent, disintegrant and glidant effects.

Why Is Silicon dioxide Used in Food and Supplements?
Synthetic amorphous silicon dioxide is the type most often used as a food additive. 
Silicon dioxide’s typically manufactured by vapor phase hydrolysis.

Which foods contain silicon dioxide? You’ll find Silicon dioxide in small amounts added to foods, such as:
-flours
-protein powders
-baking powder
-confectioner’s sugar
-salt
-spice, herb and seasoning mixtures
-beer (it is removed from the beer by filtration prior to final processing)
-dried egg products
-animal/livestock feed
-supplement capsules

Silicates are also present in a variety of plant foods included in the human diet, including vegetables and cereal grains, such as leafy greens, peppers, beets, sprouts, rice and oats.
Because it has the ability to block moisture absorption and prevent ingredients from clumping/caking together, silicon dioxide is used in food products to help retain their texture. 
Silicon dioxide’s most often found in granular or powder products, because as the U.S. Food and Drug Administration (FDA) describes it, “it increases speed of dispersion, keeping the food particles separated and permitting the water to wet them individually instead of forming lumps.”

What is silicon dioxide used for in foods and supplements? 
According to the USDA, silicon dioxide has properties that give it the following functions in foods and supplements:
-Works as an anti-caking agent
-Prevents corrosion
-Defoams
-Stops powders from absorbing moisture
-Helps to stabilize and clarify beer
-Helps carry and distribute flavoring oils
-Absorbs alcohol
-Helps in processing of wine and gelatin production
-Depending on silicon dioxide’s structure, it can appear as a transparent, tasteless, crystal or an amorphous powder (sometimes called silica powder).

Amorphous silica has a “highly unique physical and chemical properties and potential as an additive in a variety of processing industries,” as described the USDA. 
For example, it has a small particle size, high specific surface area, and gelling and thickening abilities.
Something else that makes silica unique is its solubility. Silicon dioxide is not soluble in either water or organic solvents.
In addition to being used in foods supplements and cosmetics, silica is utilized in the production of cans, impermeable films, paints, silicone rubbers, polyester compounds, dental formulations, emulsions, dry pesticides, soil conditioners and turf soil.
The production of silicon dioxide is one form of “nanotechnology,” which encompasses taking a material and making it into very tiny particles, with dimensions between one and 100 nanometers. 
This changes the material’s physical, chemical and biological properties and functions.
While nanotechnology in food processing may help improve the taste, color, look, uniformity and texture of foods, it might also change the material is absorbed and excreted in the human body.

Vulkasil
Cherts
Neosil
Neosyl
Snowit
Aerosil-degussa
Imsil
Metacristobalite
Silica vitreous
Zipax
Quartz silica
alpha-Quartz
Fossil flour
Fumed silica
Quartz dust
Rock crystal
Rose quartz
Silica dust
White carbon
Chromosorb P
Silica particles

Silicon is the second-most abundant element on Earth, behind oxygen. 
Almost 30% of our planet’s crust is made of the stuff, so Silicon dioxide isn’t surprising that it’s also found in food.
However, silicon is rarely found on Silicon dioxides own. 
Instead, Silicon dioxide combines with oxygen and other elements to form silicate materials, which are the largest class of rock-forming materials on Earth and compose 90% of the Earth’s crust. 
One such material is silica, or silicon dioxide, which is the most common component of sand.
Silica is also found naturally in some foods, and Silicon dioxide is added to many food products and supplements. 
Silicon dioxide is commonly used in the form of silicon dioxide as an anti-caking agent in foods and supplements to keep ingredients from clumping up or sticking together, and it’s sometimes added to liquids and beverages to control foaming and thickness.

Tiger-eye
Vulkasil S
Celite superfloss
Cristobalite dust
Snowtex O
Corasil II
Silver bond B
Cab-O-sperse
alpha-Cristobalite
alpha-Crystobalite
Calcined diatomite
Tokusil TPLM
Dri-Die
Gold bond R
Cabosil st-1
Manosil vn 3
Sil-Co-Sil
Ultrasil VH 3
Ultrasil VN 3

Synthetic amorphous silica (SAS, SiO2) and titanium dioxide (TiO2), the latter as a white pigment, are industrially produced in high volumes. 
SAS is used as a food additive, is manufactured by several production processes, and consists mainly of nanosized primary particles that form small aggregates and larger agglomerates. 
TiO2 as a white pigment is used as a food additive, in personal care products (e.g. toothpaste) and in many other consumer products. 
Silicon dioxide contains a fraction of nanosized primary particles (<100 nm). 
As a consequence, human exposure and subsequent systemic uptake of these particles becomes likely. 
However, only limited data are available on the presence of SiO2 and TiO2 particles in human organs. 
We reported only recently on the presence of TiO2 particles in liver and spleen. 
In this study, the focus was originally on the determination of SiO2 particles in liver, spleen, kidney and intestinal samples, however, to strengthen the results of the previous study, TiO2 particles were also measured in these new samples. 
Since the 1960s, SiO2 as an anti-caking agent and TiO2 as a white pigment are authorized food additives, and in the US as a food color additive (TiO2) and food contact substance in food packaging) and also applied in consumer and medical products. 
Sodium, calcium, and magnesium silicates and hydrated silica, SiO2. 
nH2O, contain naturally present inorganic Si. 
The latter may form small particles in the size range of 1–5 nm and can be found in natural waters, including drinking and mineral waters. 
There are limited data on the presence of TiO2 particles in the environment or in untreated food products such as raw milk, vegetables, and meat.

During the life cycle of products, release of SiO2 and TiO2 particles occurs, resulting in direct (oral, lung, and dermal) and indirect (via the environment) human exposure. 
Although human tissue levels of the element Ti and particulate TiO2 have been reported, no data are available on human tissue concentrations of the element Si and particulate SiO2. 
While no human data on the systemic uptake of SiO2 particles are available, a study with rodents implied limited oral uptake of silica at realistic consumer exposure levels. 
Uptake of TiO2 particles by the gut has been studied in animals, but rarely in humans. 
The only human volunteer studies conducted with single dose administration suggest that the oral bioavailability of TiO2 is low. 
Silicon dioxide should be noted that low oral uptake of nanomaterials can still lead to high organ burdens when there is long-term, frequent exposure in combination with low excretion or high persistence.


Aerosil bs-50
Aerosil K 7
Cabosil N 5
Carplex 30
Carplex 80
Pigment White 27
Siderite (SiO2)
Snowtex 30
Syton 2X
Tridymite 118
Zeofree 80
Cab-O-grip II
Silicon(IV) oxide, amorphous
Tridimite [French]
Amorphous silica gel

Compound Formula: O2Si
Molecular Weight: 60.09
Appearance: White Powder
Melting Point: 1,600° C (2,912° F)
Boiling Point: 2,230° C (4,046° F)
Density: 2533 kg/m-3
Solubility in H2O: N/A
Exact Mass: 59.9668 g/mol
Monoisotopic Mass: 59.967 Da

HI-Sil
Tridymite (SiO2)
Glass wool, for laboratory use
Positive sol 232
Sand, pure, 40-100 mesh
Aerogel 200
Aerosil 300
Amorphous silica dust
Ludox hs 40
Silanox 101
Silica (SiO2)
Vitasil 220
Positive sol 130M

In the current study, the presence of SiO2 and TiO2 particles in postmortem liver, spleen, kidney, jejunum, and ileum from 15 deceased persons was determined, enabled by the latest developments in analytical detection methods. 
Liver and spleen were included in this study because nanomaterials are generally taken up by the mononuclear phagocyte system (MPS) and thereby typically distribute to the liver and spleen, as well as to the kidney. 
Information on the presence of SiO2 and TiO2 particles in intestinal tissues is also considered relevant because of the reported uptake of particles by M-cells in Peyer’s patches, which are mainly found in the jejunum and ileum. 
Total-Si and total-Ti concentrations were measured using inductively coupled plasma high-resolution mass spectrometry (ICP-HRMS) while SiO2 and TiO2 particles were measured using single-particle ICP-MS (spICP-MS) on, respectively, a triple quadrupole ICP-MSMS and a ICP-HRMS and instrument. 
The tissues were further studied with high resolution scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX) to confirm the presence and size of SiO2 and TiO2 particles.

Foods With Silica
Compelling data suggests that silica is essential for your health, but more evidence is needed to confirm this. 
Typical diets likely contain enough silica that can be absorbed for potential health benefits, despite negative perceptions of silicon as dangerous.

Silicon dioxide occurs as colorless, odorless, tasteless white or colorless crystals or powder. 
Silicon dioxides many different forms can be classified as crystalline, amorphous, or vitreous. 
In crystalline forms of silicon dioxide, all of the atoms that make up the substances are arranged in orderly patterns that have the shape of cubes, rhombohedrons, or other geometric figures. 
In amorphous silicon dioxide, silicon and oxygen atoms are arranged randomly, without any clear-cut pattern. 
Vitreous silicon dioxide is a glassy form of the compound that may be transparent, translucent, or opaque. 
The various forms of silicon dioxide can be converted from one form to another by heating and changes in pressure.

An especially interesting form of silicon dioxide is silica gel, a powdery form of amorphous silicon dioxide that is highly adsorbent. 
An adsorbent material (in contrast to an absorbent material) is one that is capable of removing a material, such as water, ammonia, alcohol, or other gases, out of the air. 
The second material bonds weakly to the outer surface of silica gel particles. 
Silica gel is able to adsorb anywhere from 30 to 50 percent of its own weight in water from the surrounding atmosphere before it becomes saturated. 
The silica gel is not chemically altered by the process of adsorption and still feels dry even when saturated. 
The adsorbed water can be driven off simply by heating the silica gel, allowing the material to regain its adsorbent properties.

HOW Silicon dioxide IS MADE
Although methods are available for synthesizing silicon dioxide, there is no practical reason for doing so. 
The abundant quantities of silicon dioxide found in the earth's crust are sufficient to satisfy all industrial needs. 
Among the minerals and earths that contain silicon dioxide in an uncombined form are quartz, flint, diatomite, stishovite, agate, amethyst, chalcedony, cristobalite, and tridymite.

Siliceous earth, purified (NF)
Siliceous earth, purified [NF]
Silicon Oxide Hollow Nanospheres
Aerosil A 300
Aerosil E 300
Aerosil M-300
Nyacol 830
Sibelite M 3000
Sibelite M 4000
Sibelite M 6000
Quazo puro [Italian]
Caswell No. 734A
Nalfloc N 1050
Quso 51
Sicron F 300
Sikron F 100
Spectrosil
Accusand
Coesite
Fuselex
Nalcast
Nyacol 1430
Optocil
Quartzine
Quarzsand
Rancosil
Suprasil
Tridimite

Silica (quartz); "Silica," or silicon dioxide (SiO2), occurs in either a crystalline or noncrystalline (amorphous) form. 
Quartz is a colourless, odourless, non-combustible solid and a component of many mineral dusts.
Silica(quartz);Silica(quartz) is an industrial material, its sand is often used for glass making. 
Silicon dioxide is retrieved my mining and a limited environmental impact on earth.
Silica (quartz): Silica also called Silicon Dioxide, compound of the two most abundant elements in the Earth's crust. 
Silica has three main crystalline varieties: quartz (by far the most abundant), tridymite, and cristobalite.
Silica (Quartz) : Quartz, the second most common mineral on the earth's crust, belongs to the rhombohedral or trigonal crystal system and can be manufactured using hydrothermal processes in autoclaves.

Silica, amorphous fused
Siltex
Vitreous quartz
Vitreous silica
Tridymite dust
W 12 (Filler)
beta-Quartz
Fused quartz
MIN-U-sil alpha quartz
Quartz-beta
Quso G 30
Silica glass
Amorphous quartz
Dri-Die insecticide 67
Nalco 1050
Quazo puro
Silica, amorphous, fumed
Vitrified silica
MFCD00163736
Pyrogenic colloidal silica
Sand, for analysis, 40-100 mesh
Silica gel, spherical, 60 angstroms

Silicon dioxide, also known as synthetic amorphous silica (SAS), is widely used in food products as a thickener, anticaking agent, and carrier for fragrances and flavors.
Derived from naturally occurring quartz, silicon is the most abundant mineral in the earth’s crust. 
Silicon dioxide’s also naturally found in water and plant-based foods, especially cereals like oats, barley and rice.
Silicon should not be confused with silicone, a plastic material that contains silicon and other chemicals used to make breast implants, medical tubing and other medical devices.

Synthetic amorphous silica
Hydrophobic silica 2482
Silica, fused
Suprasil W
Vitreosil IR
Borsil P
Calcined diatomaceous earth
Silica gel, spherical, 100 angstroms
Silica gel, spherical, 300 angstroms
Silane, dioxo-
Crystallized silicon dioxide
Optocil (quartz)
CP-SilicaPLOT
Diatomaceous earth, calcined
Silicon oxide, di- (sand)
Quarzsand [German]
S-Col

Applications
Silicas exist as white, fluffy powders that are produced through a wet process, yielding silica or silica gel, or a thermal route, yielding pyrogenic (fumed) silica.
In powdered foods, the silica clings to the particles of the foods and prevents them from clumping. 
This allows powdery products to remain free-flowing, and other products easy to separate.
Silicon dioxide also functions as a defoaming agent, carrier, conditioning agent, chillproofing agent in malt beverages (like beer) and filter aid.
Silicon dioxide’s also used to manufacture materials such as adhesives and paper for food-packaging materials.
As a direct additive, per U.S. FDA regulation, levels of SAS cannot exceed 2% by weight of the food, and as an indirect additive, it can only be used in the amount required to produce the intended functional effect.

Linear Formula: SiO2
MDL Number: MFCD00011232
EC No.: 262-373-8
Beilstein/Reaxys No.: N/A
Pubchem CID: N/A
IUPAC Name: Dioxosilane
SMILES: O=[Si]=O
InchI Identifier: InChI=1S/O2Si/c1-3-2
InchI Key: VYPSYNLAJGMNEJ-UHFFFAOYSA-N

Admafine SO 25H
Admafine SO 25R
Admafine SO 32H
Admafine SO-C 2
Admafine SO-C 3
Cristobalite asbestos
Keatite (SiO2)
Sg-67
Silica, amorphous, fumed, cryst.-free
Fumed silica, crystalline-free
Stishovite (SiO2)
ED-C (silica)
Fuselex ZA 30
As 1 (silica)
CCRIS 2475
CCRIS 3699
DQ12
Agate (SiO2)
Celite 545

Silica, also called silicon dioxide, compound of the two most abundant elements in Earth’s crust, silicon and oxygen, SiO2. 
The mass of Earth’s crust is 59 percent silica, the main constituent of more than 95 percent of the known rocks. 
Silica has three main crystalline varieties: quartz (by far the most abundant), tridymite, and cristobalite. 
Other varieties include coesite, keatite, and lechatelierite. 

Dimethyl siloxanes and silicones
Fumed synthetic amorphous silica
Silica, crystalline - tridymite
FB 5 (silica)
Fuselex RD 120
Corning 7940
Microcrystalline quartz
Synthetic amorphous silica, fumed
Denka F 90
Denka FB 30
Denka FB 44
Denka FB 74
Denka FS 30
Dri-Die 67
Silica gel spherical, 40-75 mum particle size
WGL 300

Silicon dioxide has a molecular weight of 60.08 g/mol. 
Silicon dioxide has the lowest coefficient of expansion by heat of any known substance. 
Silica is not soluble in either water or organic solvents, but it is soluble in hydrofluoric acid. 
Heating with concentrated phosphoric acid may slowly dissolve silicon dioxide as well. 
Silicon dioxide exists in the crystalline and amorphous forms. 
Their physical states are easily differentiated by X-ray diffraction; the crystalline form exhibits a well-defined diffraction pattern while the amorphous form does not. 
The density of crystalline silica (e.g. quartz) and amorphous silica are 2.65 and 2.2 g/cm3 36 , respectively. 
Silica is transparent, tasteless, crystal or amorphous powder. 
The amorphous form of silica may be dissolved by hot concentrated alkaline solutions, but the crystalline form of silica generally is not soluble

Cryptocrystalline quartz
FB 20 (silica)
Elsil 10
F 44 (filler)
D & D
SF 35
Elsil BF 100
F 125 (silica)
F 160 (silica)
Silicon dioxide, 99.998%, (trace metal basis)
Fuselex RD 40-60
Silica, amorphous, fused
Silicon dioxide, chemically prepared
EINECS 231-545-4
EINECS 238-455-4
EINECS 238-878-4
EINECS 239-487-1
HK 400
TGL 16319

Silicon Dioxide, SiO2, is the low-index, low absorption material used in combination with high-index oxide layer coatings that operate in the UV (~200 nm) to IR (~3 μm) regions. 
Typical applications include antireflection coatings for near-UV laser optics, all-dielectric mirrors, beam-dividers, bandpass filters, and polarizers. 
Silica can be used in combination with specific high-index layers, for example Hafnia, Zirconia, and Tantala, to form multilayer structures with high damage thresholds for specialized UV laser applications. 
Silica films sometimes are useful in promoting adherence between two dissimilar materials, especially oxide-compositions. 
In contrast to the parent quartz form, Silica films are amorphous and never obtain the equivalent density, hardness or water impermeability of the crystal form.

Film Properties
Completely oxidized silica films are absorption-free over the range below ~250 nm to at least 5 μm. 
Film layers are amorphous and smooth. High mechanical compressive stress limits the thickness the single layer thickness. 
When starting from Silica pieces, little dissociation and oxygen loss occurs during evaporation, and it is not always necessary to provide a background pressure of oxygen to obtain low-absorbing films. 
Adhesion is good to glass, most other oxides, and some polymers. 
The films generally grow with an amorphous structure and relatively high packing density so they exhibit minimum index changes when vented to moist air. 
The appearance of water absorption bands near 2.9 and 6.2 μm indicates less than perfect packing density. 
The refractive index is maximized and water band absorption is minimized with the use of high energy deposition techniques such as IAD or sputter deposition and high substrate temperature. 
Low absorption SiO2 films can be produced by oxidizing Silicon Monoxide in a reactive oxygen background. 
Evaporation would proceed from a baffled box and therefore the possibility of generating micro-particulates is eliminated. 
Alternatively, evaporation can proceed from flat surfaces of large pieces of Silicon Monoxide that are swept by a low-power e-beam. 
Films so deposited exhibit low optical absorption, but the possibility exists for particulate emission.

Refractive Index
The refractive indices are dependent on the degree of oxidation, the substrate temperature, and the deposition energy. 
The curve below shows typical values. 
They can be slightly higher than values for fused Silica.

Celite(R), for analysis, high purity analytical grade
Silica gel 60, 0.060-0.2mm (70-230 mesh)
Silica, crystalline quartz
Silicon dioxide (vitreous)
EPA Pesticide Chemical Code 072605
Silica 2482, hydrophobic
CI 7811
Silica, crystalline, quartz
Silica, crystalline: quartz
GP 7I
Silica gel, for chromatography, 0.030-0.200 mm, 60 A
Silica gel, for chromatography, 0.035-0.070 mm, 90 A
Silica gel, for chromatography, 0.075-0.250 mm, 150 A
Silica gel, for drying purposes, non-toxic grade, 3-6 mm
CAB-O-SIL N-70TS
Silica, crystalline tridymite
Kieselgel
Silica, crystalline - quartz
AF-SO 25R
Quartz [Silica, crystalline]

Physical Properties of Solid Material:
Molecular Weight: 60
Melting Point: 1700° C
Color: Clear to white (see item description)
Crystal Density: 2.17g/cc
Evaporation Parameters
Evaporation temperature: ~1200° C
Source Container: No liner for E-beam
Rate: 2 Å/sec.
Partial pressure of oxygen: 1 x 10-5 Torr
Substrate temperature: 200° C to 300° C
Quartz crystal monitor Z-ratio: 1
Forms and Sizes: Available
Materion Advanced Chemicals offers materials for evaporation as well as sputtering targets.

Silicon dioxide, also known as silica, is the most abundant mineral in the Earth's crust, and it is found on every continent in forms ranging from fine powders to giant rock crystals. 
In addition to having a natural beauty in its raw mineral form, the substance has useful properties with important applications in everyday life.

Silica gel, for column chrom., ultrapure, 60-200 $6, 60A
Zorbax
quartz-glass
Silicom dioxide
Silica flour (powdered crystalline silica)
Silica, crystalline: tridymite
silica-gel
Fused-silica
Silica,fumed
silicium dioxide
AI3-25549
GP 11I
RD 8
silica-
Silica, fumed

Production of Silicon Dioxide
Amorphous silica or precipitated silica is obtained by the acidification of sodium silicate solutions. Silica gel is washed and dehydrated to produce colourless microporous silica. The reaction involving a trisilicate along with sulphuric acid is given below:

Na2Si3O7 + H2SO4 → 3SiO2 + Na2SO4 + H2O

Silicon Dioxide Reactions
Silica gets converted to silicon by reducing with carbon.

Fluorine when reacted with silicon dioxide it produces SiF4 and O2.

Silicon dioxide reacts with hydrofluoric acid to produce hexafluorosilicic acid (H2SiF6).

SiO2 + 6HF → H2SiF6 + 2H2O

Health hazards
Silica when ingested orally is non-toxic. 
As per a study conducted in the year 2008, found that the higher the levels of silica in water, the risk of dementia decreased. 
Therefore, the dose was increased to 10 mg/day of silica in drinking water as the risk of dementia decreased. 
When finely divided crystalline silica dust is inhaled, it can lead to bronchitis, lung cancer, or silicosis, due to the lodging of dust in the lungs. 
When fine silica particles are inhaled in large enough quantities, it increases the risk of rheumatoid arthritis and lupus.

Frequently Asked Questions
What are the uses of silicon dioxide?
Approximately 95 per cent of the industrial usage of silicon dioxide (sand) exists in the building industry, e.g. for concrete production (Portland cement concrete). 
Silica, in the form of sand, is used as the key ingredient for the manufacture of metallic components in engineering and other applications of sand casting. 
The relatively high melting point of silica allows for its use in these applications.

How is silicon dioxide produced?
Mostly, silicon dioxide is obtained via mining activities including sand extraction, and quartz purification. 
Quartz is suitable for many purposes, whereas chemical processing is needed to render a more suitable product (e.g. more reactive or fine-grained) purer or otherwise. 
Silica fume is derived from hot processes such as the processing of ferrosilicon as a by-product.

U 333
W 006
Silicon di-oxide
Tridymite [Silica, crystalline]
CRS 1102RD8
Silica Dispersion
SiO2 Nanopowder
Silica gel G
Silica, crystalline: cristobalite
Silica, tridymite
SiO2 Nanospheres
Diatomaceous earth, flux-calcined, filter aid, treated with sodium carbonate, flux calcined
Silica gel 60 ADAMANT(TM) on TLC plates, with fluorescent indicator 254 nm
EF 10
FS 74
MR 84
Silica, crystalline - cristobalite
Silica Microspheres

Silicon dioxide Features
A crystalline solid at normal temperatures, pure silicon dioxide is white in color and has a density of 2.2 grams per cubic centimeter. 
Silicon dioxide is composed of one atom of silicon and two atoms of oxygen; the atoms are bound together tightly making it resistant to many harsh chemicals.
In nature, it takes the form of sand or quartz crystals, and is relatively hard compared to most minerals. 
Silicon dioxide is highly resistant to heat, with a melting point of 1,650 degrees Celsius (3,000 degrees Fahrenheit).

Silicon dioxide Types
Although sand and quartz crystals may appear different, they are both made primarily of silicon dioxide. 
The chemical makeup of these types is exactly the same, and the properties are generally the same, but they were formed under different conditions. 
Sand particles are very small, but tough and hard. 
Some quartz crystals have a milky-white appearance. 
So-called milky quartz is quite abundant, so it is common to find large rocks of this type of quartz. 
Mineral impurities can turn quartz purple, light pink, or other colors, resulting in precious or semi-precious stones such as:
-amethyst
-citrine
-rose quartz
-smoky quartz

Silicon dioxide Functions
Silicon dioxide is used in a number of different ways. 
One of the most common uses is to make glass, which is superheated and pressurized silicon dioxide. 
Silicon dioxide is also manufactured for use in toothpaste. 
Because of its hardness, it helps to scrub away plaque on teeth. 
Silicon dioxide is also a major ingredient in cement and used as a pesticide. Silica gel is a food additive and desiccant that helps absorb water.

Warning
While silicon dioxide is for the most part harmless, it poses health risks when inhaled. 
In powder form, small particles of the mineral can lodge in the esophagus and the lungs. 
Silicon dioxide does not dissolve in the body over time, so it builds up, irritating sensitive tissues.
One such condition is called silicosis, which causes shortness of breath, fever, and coughing and causes the skin to turn blue. 
Other conditions include bronchitis and, rarely, cancer.

Silicon dioxide Geography
Silicon dioxide is found just about everywhere in the world, as it is the most common mineral in the crust. 
On the surface of the earth, it is prevalent in rocky or mountainous regions. 
Silicon dioxide is also present in the form of sand in the deserts and coasts of the world.

Cristobalite [Silica, crystalline]
Silica gel, functionalized, (cyclohexylcarbodiimido)propyl, ca. 0,9 mmol-g, particle size: 40-63 micron
Amorphous silica: Pyrogenic (fumed)
EINECS 262-373-8
Silica gel, ASTM
Silica Nanoparticles
Methyl3-oxohexanoate
Siliceous sand, CP
BF 100
EQ 912
QG 100
RD 120
Celite 503
Nettles p.e. extract
Silicon Dioxide Powder
Silica, fumed, powder
Silicon dioxide (NF)
Activated Silica Powder
Activated Silicon Oxide
Sand 50-70 mesh
F 44

The Silicon Dioxide (SiO2) Support Films are manufactured using the PELCO® 200nm Silicon Nitride Support Films with the 0.5 x 0.5mm window on a perfectly round 3mm Si frame as a platform. 
The silicon dioxide support films consist of pure and amorphous thermal SiO2 membrane. 
The 0.5 x 0.5mm membrane is patterned into 24 ea. apertures with a size varying between 50 x 50µm to 70 x 70µm and etched back to the thermally-deposited amporhous Silicon Dioxide leaving a structure-free SiO2 thin membrane of 40nm, 18nm or 8nm, suspended by a 200nm optically transparent Silicon Nitride support mesh. 
The bar size between the SiO2 apertures is 25-35µm and the boundary width is 25-55µm. 
The design of the mesh and the ratio of mesh suspension and Silicon Dioxide Film has been optimized to enable flat Silicon Dioxide Support Films with a size of 50 x 50µm to 70 x 70µm. 
The result is a Silicon Dioxide membrane with a truly superior flatness, ideal for TEM imaging. 
Silicon Dioxide, the compression in the SiO2 film is balanced by the stress in the Silicon Nitride grid structure. 
The mesh size of the Silicon Dioxide Support Films is comparable to the area size found on most 300 and 400 mesh TEM grids and is considered to be a practical size for many applications. 
There are 24 fields of SiO2 support films on each frame. 
The boundary of 200nm Silicon Nitride membrane leaves ample area for experiments on Silicon Nitride.

Si/SiO2 wafers from ACS Material are the industry standard for high-quality substrates. 
Our high-quality violet wafers are packaged in a 1000 class cleanroom and provide optimal visibility for a variety of nanomaterials, including CVD graphene and graphene flakes.
Silicon/silicon dioxide substrates are ideal for a variety of uses, including as FET substrates, or in X-ray studies, surface microscopy analysis, or to assist with ellipsometry measurements. 
Our Si/SiO2 wafers are polished on the front, etched on the back, and fit in a substrate rack for convenient batch processing and cleaning. 
ACS Material provides leading researchers and engineers around the world with the highest-quality nanomaterials and other supplies. 
We take pride in our reputation for the purity and consistency of our materials, for the quality of our customer service, and for the fairness of our prices.
Our team is available to answer all your questions to make certain you get the materials you need to take your research to the next level.

Silica gel, large pore
Y 40
SiO2.xH2O
Hollow Silica Nanosphere
Silicon Oxide Dispersion
Silicon Oxide Nanopowder
Activated Silicon Dioxide
Crystalline Silica Quartz
Silica gel, ACS reagent
Cab-O-sil(R) M-5
Celite(R) 512 medium
Kieselguhr, -325 mesh
Silica, 99.8%
SBA-15 Molecular Sieve
Silicon dioxide Nanopowder
Diatomaceous earth, powder
DSSTox_CID_9677
Silicon Dioxide Dispersion
Epitope ID:158537
Silica, fumed, hydrophobic
Silicon Dioxide Nanospheres
Silicon Oxide Nanoparticles

Crystalline silicon dioxide has been associated with pulmonary lung disease. 
A number of descriptive terms such as “amorphous silica,” “free silica,” “silica flour,” and “fumed silica” have arisen in the literature as a result of studies related to health and the silicon dioxide forms. 
The definition of these terms has been the result of limitations (both analytical and physical) in qualitative and quantitative analytical methods, as well as definitions associated with the type of manufacturer or process producing the silicon dioxide. 
X-ray diffraction and typical mineralogical nomenclature are relevant for the definition of crystalline silicon dioxide polymorphs, but other silicon dioxide materials require alternative techniques for analytical definition of those properties which may be health related.

OTHER NAMES:
Silica, quartz, sand, amorphous silica, silica gel, and others

FORMULA:
SiO2

ELEMENTS:
Silicon, oxygen

COMPOUND TYPE:
Nonmetallic oxide (inorganic)

STATE:
Solid

MOLECULAR WEIGHT:
60.08 g/mol

MELTING POINT:
Varies depending on crystalline state; typically above 1700°C (3100°F)

BOILING POINT:
2950°C (5300°F)

SOLUBILITY:
Solubility depends on crystalline state; generally insoluble in water; soluble in many acids and alkalis

EC 231-545-4
Celite(R) 503, CP
Celite(R) 535, CP
Celite(R) 545, CP
Nano Silicon Dioxide Powder
DSSTox_RID_78805
DSSTox_GSID_29677
Silicon dioxide, acid washed
Silicon(IV) oxide (SiO2)
13778-37-5
13778-38-6
15723-40-7
17679-64-0
99439-28-8
Silica fibers, 1/4'' long
Kieselguhr, calcined, purified
Silica gel, CP, blue, beads

Silicon dioxide General description
Silicon dioxide (SiO2) exists in three crystalline forms, namely quartz, tridymite and cristobalite. 
Silicon dioxide reacts with hydrofluoric acid to form silicon tetrafluoride (SiF4) and water. Silicates are formed on reacting SiO2 with alkali melts. 
SiO2 is the main component in glass, brick and concrete and also forms the insulator in silicon devices. 
The alteration of the surface of SiO2 with (3-aminopropyl)triethoxysilane (APTES) for binding lactate dehydrogenase (LDH) to form an amino layer has been reported. 
The silicon-silicon dioxide structure has been investigated at liquid nitrogen temperature by electron spin resonance spectra.

Silicon dioxide Application
Silicon dioxide may be used to produce silicon by electrochemical reduction in the presence of calcium chloride (CaCl2) electrolyte. 
Silicon dioxide may also be used to prepare FeCl3/SiO2, a supported reagent for the oxidative coupling reactions.

Silica Nanoparticles Dispersion
Silica, fused, respirable dust
25wt% Silicon Oxide in Water
AW Standard Super-Cel(R) NF
MCM-41
Silica gel, CP, mixed, beads
Silica gel, CP, white, beads
Silicates (<1% crystalline silica):Graphite, natural
Hyflo(R) Super-Cel(R), CP
CHEMBL3188292
DTXSID1029677
Filter agent, Celite(R) 545
Sand, white quartz, CP, beads
Quarz cryst., 0.6-1.3 mm
Silicon dioxide, colloidal (NF)
Diatomaceous earth, flux-calcined
Silicon dioxide, SAJ first grade
Diatomaceous earth non-washed, CP
Silica Gel Dessicant (Grade 03)
Silica gel, CP, blue, bead size
Filter agent, Celatom(R) FW-14
Filter agent, Celatom(R) FW-50
Filter agent, Celatom(R) FW-60
Filter agent, Celatom(R) FW-80
Silica, fused [Silica, amorphous]
Silicon dioxide, JIS special grade
Silicon Oxide Mesoporous Nanopowder

Silicon dioxide, also known as silica, has a chemical formula of SiO2. 
Silicon dioxide has a melting point of 1,610°C, a density of 2.648 g/cc, and a vapor pressure of 10-4 Torr at 1,025°C. 
Silicon dioxide is commonly found in nature as sand or quartz. 
Silicon dioxide is primarily used in the production of glass for windows and beverage bottles. 
Silicon dioxide is evaporated under vacuum for the fabrication of optoelectronic and circuit devices.

Assay Percent Range 44.5 to 47.9% (Si)
Linear Formula SiO2
Solubility Information    Solubility in water: insoluble
Formula Weight 60.08
Physical Form Solution
Percent Purity 99.998%
Grade Trace Metal Basis
Packaging Glass bottle
Total Trace Metal Impurities 20ppm max.
Color Colorless to Yellow
Melting Point 1610.0°C
Quantity 5g
Chemical Name or Material Silicon dioxide

We recommend heating the substrate to 350°C before attempting to thermally evaporate silicon dioxide. 
We anticipate a deposition rate of 2 angstroms per second when the evaporation temperature is at ~1,200°C. 
A partial pressure of O2 at 1-2 X 10-4 Torr is recommended. 
Under these parameters, we anticipate films to be smooth and amorphous. 
The material should be replaced when Silicon dioxide becomes dark or black.
Thermal evaporation of silicon dioxide is generally not done due to the difficulty associated with this method. 
The simplest approach would be to use a relatively inexpensive boat source and change the material as often as possible. 
We recommend starting with a thick gauge, Tungsten boat such as our EVS20A015W. 
The other option would be to use a tantalum baffle box, like our EVSSO22. 
In order for silicon dioxide to sublime and evaporate, the temperature of the baffle box must be between 1,500°C and 1,800°C. 
Once the material's temperature is within this range, there is potential for the material to alloy with the box, causing it to fail. 
Silicon dioxide mimics silicon when in the melted state.
Another option would be reactive evaporation. 
Silicon monoxide (SiO) can be placed in a tantalum baffle box with a substantial amount of oxygen (we recommend adding 1-2 X 10-4 Torr). 
We have not encountered any problems thermally evaporating silicon monoxide. 
However, Silicon dioxide is necessary to replace the material after every run. 
Silicon monoxide is hard to convert to silicon dioxide because the bond energy for silicon monoxide is higher than that for silicon dioxide. 
As with silicon dioxide, the temperature of the baffle box must be between 1,500°C and 1,800°C in order for evaporation to take place. 
Once the material's temperature is within this range, there is potential for the material to alloy with the box, causing it to fail. 
Silicon monoxide also mimics silicon when in the melted state.

AMY37125
Chromosorb(R) G, 80-100 mesh
2-Mercaptoethyl ethyl sulfide silica
Celite(R) 545 AW, reagent grade
Silica gel 60, 230-400 mesh
Silica Hollow Nanospheres Dispersion
Silicon(IV) oxide, electronic grade
Tox21_301288
MFCD07370733
Sand, white quartz, CP, crystalline
Silica gel, indicating, 6-16 mesh
Chromosorb(R) W/AW, 45-60 mesh
Light anhydrous silicic acid (JP17)
Quarz fine, cryst., 0.4-0.8 mm
Silica gel, 70-200 mesh (TLC)
Silica, fumed, powder, 0.008 mum
AKOS009085429
Silica Gel, 40-63 Micron Particles
Silicon Dioxide Nanospheres Properties
DB11132

How Silicon dioxide works
Silicon dioxide causes small abrasions on the body of any pest that comes into contact with the powder. 
The pest gradually loses its body fluids, dehydrates and dies.
When bait is added, pests tend to eat the product. 
The crystals then abrade their digestive systems and kill them.
Silicon dioxide may take a few days to eliminate pests after the pesticide is applied.

Silicon dioxide Application
The product should be applied to pests or to spots that they frequent. 
Silicon dioxide may be sprinkled directly on the leaves of affected plants, avoiding flowers so as not to harm pollinating insects. 
Silicon dioxide may also be applied to the soil (without working it in) around the base of plants to be protected.
Silicon dioxide is best to apply Silicon dioxide during dry weather, because silicon dioxide loses its effectiveness when wet.

Precautions
The product may irritate the respiratory tract if inhaled, so it is best to wear a mask when applying it. 
In addition, because it may irritate the eyes, it is best to wear goggles. 
Silicon dioxide should be applied on calm days, to keep it from drifting.
Pesticides with silicon dioxide as the active ingredient are not selective and may harm beneficial garden organisms such as earthworms. 
This means that they should be used only as a last resort and for spot treatment only.
Do not use near any body of water or wetland, or dump any pesticide or rinse your equipment there, as this will contaminate the water. 
Never dump pesticides down sewers.
Keep out of reach of children. 

Iron Sulfide (FeS) Sputtering Targets
Silicon Dioxide Nanoparticle Dispersion
Glass spheres, 9-13 mum particle size
Quartz (silicon dioxide), silver, pure
Silica gel, CP, white, medium granules
Silica gel, technical grade, 3-9 mesh
Silica, mesostructured, HMS (wormhole)
NCGC00257531-01
Sand, white quartz, purum p.a., powder
Silica gel orange, granular, 0.2-1 mm
Silicon Oxide Nanoparticles / Nanopowder
Silicon(IV) oxide, powder, 0.5 micron
Silicon(IV) oxide, powder, 1.0 micron
Silicon(IV) oxide, powder, 1.5 micron
14639-89-5
92283-58-4
E551

Silicon dioxide (diatomaceous earth) is made up of approximately 90% silica, the same as is in quartz, sand and agate. 
The type of silica found in diatomaceous earth is predominately amorphous silica but will contain small amounts of crystalline silica (which is associated with severe lung toxicity).
Crystalline silica is classified as a known human carcinogen but amorphous silica is not classifiable as to human carcinogenicity. 
According to product registration staff at the Washington State Department of Agriculture, all products registered in Washington with silicon dioxide as the active ingredient contain amorphous silica. 
The EPA includes crystalline-free silica in the list of minimal risk inert ingredients and the FDA allows it to be added to food at rates up to 2% by weight.

Silica gel, CP, blue, bead size, medium
Silica gel, technical grade, 6-16 mesh
Silicon oxide powder, 99% Nano, 20 nm
CAS-7631-86-9
Silica gel desiccant, -3+8 mesh granules
Silica gel, 12-24 mesh (liquid drying)
Silica gel, CP, mixed, bead size, medium
Silica gel, for column chromatography, 60
Silicon Dioxide Nanoparticles / Nanopowder
Celite(R) 281, filter aid, flux calcined
Celite(R) S, filter aid, dried, untreated
Chromosorb(R) W/AW-DMCS, 80-100 mesh
Quarz min. 99% powdered, up to 125 ?m
Silica gel desiccant, -6+12 mesh granules
Silicon dioxide, purum p.a., acid purified
White Silica Gel Beads, 3 mm (2-5 mm)

Two other forms of silicon dioxide are not true polymorphs. Lechatelierite, an amorphous silicon dioxide, was found at the Barringer Meteor Crater in 1915. 
Softer and less dense than quartz, it forms when the heat and pressure of meteoric impacts and lightning fuse quartz sand. 
With its noncrystalline structure, lechatelierite is not a mineral, but a mineraloid.
Silicon dioxide occurs in lighting-strike-formed “Libyan desert glass” and in “trinitite,” a glass created when heat from the 1945 nuclear detonation at New Mexico’s Trinity Site altered quartz sand.

In 1984, mogánite, a partially hydrated silicon dioxide and thus not a true polymorph, was discovered on Spain’s Canary Islands. 
Softer and less dense than quartz, Silicon dioxide crystallizes in the monoclinic system. 
Mogánite forms from the devitrification of amorphous opaline silica.
In the future, mineralogists expect to identify additional polymorphs and related forms of silicon dioxide to further demonstrate that, while all quartz is indeed silicon dioxide, all silicon dioxide is not quartz.

FT-0624621
FT-0645127
FT-0689145
FT-0689270
FT-0696592
FT-0696603
FT-0697331
FT-0697389
FT-0700917
Quartz rod, fused, 2.0mm (0.079in) dia
Quartz rod, fused, 5.0mm (0.197in) dia
S0822
Silica gel, with 1-4 mm moisture indicator
Silica, amorphous, fumed (crystalline free)
Silicon dioxide Nanopowder KH550 processing
Silicon dioxide Nanopowder KH570 processing
Celite(R) 110, filter aid, flux calcinated
Celite(R) 512 medium, filter aid, calcined
Chromosorb(R) G/AW-DMCS, 100-120 mesh
Chromosorb(R) W/AW-DMCS, 120-140 mesh
K-411 Glass microspheres, NIST SRM 2066
Quartz rod, fused, 10.0mm (0.394in) dia
Silica gel, technical grade 40, 6-12 mesh
C18 Silica Gel, Endcapped, 60A, 40-63um
D05839
D06521
D06522

The chemical compound silicon dioxide, also known as silica (from the Latin silex), is an oxide of silicon with the chemical formula SiO2. 
Silicon dioxide has been known for Silicon dioxides hardness since antiquity. Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms.
Silica is manufactured in several forms including fused quartz, crystal, fumed silica (or pyrogenic silica, trademarked Aerosil or Cab-O-Sil), colloidal silica, silica gel, and aerogel.
Silica is used primarily in the production of glass for windows, drinking glasses, beverage bottles, and many other uses. 
The majority of optical fibers for telecommunications are also made from silica. 
Silicon dioxide is a primary raw material for many whiteware ceramics such as earthenware, stoneware, porcelain, as well as industrial Portland cement.
Silica is a common additive in the production of foods, where it is used primarily as a flow agent in powdered foods, or to absorb water in hygroscopic applications. 
Silicon dioxide is the primary component of diatomaceous earth which has many uses ranging from filtration to insect control. 
Silicon dioxide is also the primary component of rice husk ash which is used, for example, in filtration and cement manufacturing.
Thin films of silica grown on silicon wafers via thermal oxidation methods can be quite beneficial in microelectronics, where they act as electric insulators with high chemical stability. 
In electrical applications, Silicon dioxide can protect the silicon, store charge, block current, and even act as a controlled pathway to limit current flow.
A silica-based aerogel was used in the Stardust spacecraft to collect extraterrestrial particles. 
Silica is also used in the extraction of DNA and RNA due to its ability to bind to the nucleic acids under the presence of chaotropes. 
As hydrophobic silica Silicon dioxide is used as a defoamer component. In hydrated form, it is used in toothpaste as a hard abrasive to remove tooth plaque.
In Silicon dioxides capacity as a refractory, Silicon dioxide is useful in fiber form as a high-temperature thermal protection fabric.
In cosmetics, Silicon dioxide is useful for its light-diffusing properties and natural absorbency. 
Colloidal silica is used as a wine and juice fining agent. In pharmaceutical products, silica aids powder flow when tablets are formed. 
Finally, Silicon dioxide is used as a thermal enhancement compound in ground source heat pump industry.

Sand, white quartz, 50-70 mesh particle size
Silica gel, large pore, P.V. ca. 1.65cc/g
Silica, mesostructured, MSU-F (cellular foam)
Silicon(IV) oxide, 99.999% (metals basis)
Celite(R) 209, filter aid, natural, untreated
Celite(R) Analytical Filter Aid II (CAFA II)
Glass sand, NIST(R) SRM(R) 165a, low iron
Silica gel spherical, 75-200 mum particle size
Silica gel, Davisil(R) grade 922, -200 mesh
Silicon Oxide (Silica, Silicon dioxide, quartz)
Silicon oxide powder, 99.5% Nano, 15-20 nm
Diatomaceous earth, calcined, filter aid, calcined
Q116269

Silicon dioxide is a common mineral that can be found under different forms (crystalline or amorphous) and is also found in many clays and diatomaceous earth. 
The purpose of this trial was to assess, in a factorial 2×2 arrangement, the growth performance of piglets reared with a feeding program including, or not, a crystalline silica-based feed supplement (SI) with or without antibiotics as growth promoters (AGP; chlortetracycline and high levels of Cu and Zn in Phase 1 and chlortetracycline in Phase 2). 
All diets were formulated to be iso-caloric and iso-nitrogenous. 
An ANOVA was performed on zootechnical parameters with the pen as the experimental unit for all analyses. 
Effects of AGP, SI, block (based on sex and body weight), and interaction between AGP and SI were included in the statistical model. 
A total of 252 piglets with body weights of 7 kg were reared until 24 kg of body weight and allocated into 36 pens. 
According to these results, groups fed with AGP showed improved weight gain, feed intake, and feed conversion during Phase 1, while no significant effect was observed during Phase 2. 
Concerning the effect of SI, feed intake was improved by 4.13% during the overall nursery period, compared to groups without SI (729 versus 700 g/day; P < 0,05). 
In addition, groups fed SI showed an average daily gain of 3.26% higher than animals without SI during the same period (607 versus 588 g/day; P < 0.05). 
This effect leads to an improvement of 2.2% in piglet's weight at the end of the post-weaning phase (24.52 versus 23.99 kg; P < 0.05). 
Silicon dioxide was concluded that under our trial conditions, adding crystalline silicon dioxide to piglet feed (0.02%) increase feed intake, growth rate, and piglet weight at the end of the nursery period. 
This mineral additive could offer potential economic benefits to swine producers.

Sand for sand sieve analysis, NIST(R) RM 8010
Silica gel, GF254, for thin layer chromatography
Silica gel, HF254, for thin layer chromatography
Silica gel, Type III, Indicating, for desiccation
Silica, mesostructured, MCM-41 type (hexagonal)
Silicon dioxide, purum p.a., acid purified, sand
Standard Super Cel(R) fine, filter aid, calcined
Celite(R) 500 fine, filter aid, dried, untreated
Glass sand, NIST(R) SRM(R) 1413, high alumina
J-002874
Sand, white quartz, >=99.995% trace metals basis
Silica gel, large pore, P.V. ca. 1cc/g, 8 mesh
Silica gel, technical grade, 1-3 mm particle size
Silica gel, technical grade, 3-6 mm particle size
Silica gel, with moisture indicator (blue), coarse
Celpure(R) P65, meets USP/NF testing specifications
Metal scavenging agent, mercaptopropyl modified silica
Micro particles based on silicon dioxide, size: 2 mum
Micro particles based on silicon dioxide, size: 3 mum
Micro particles based on silicon dioxide, size: 4 mum
Micro particles based on silicon dioxide, size: 5 mum
Quartz lid for 30ml quartz crucible, fused, ID 48mm

SiO2 has a number of distinct crystalline forms (polymorphs) in addition to amorphous forms. 
With the exception of stishovite and fibrous silica, all of the crystalline forms involve tetrahedral SiO4 units linked together by shared vertices in different arrangements. 
Silicon-oxygen bond lengths vary between the different crystal forms, for example in α-quartz the bond length is 161 pm, whereas in α-tridymite it is in the range 154–171 pm. 
The Si-O-Si angle also varies between a low value of 140° in α-tridymite, up to 180° in β-tridymite. In α-quartz the Si-O-Si angle is 144°.
Fibrous silica has a structure similar to that of SiS2 with chains of edge-sharing SiO4 tetrahedra. 

Stishovite, the higher pressure form, in contrast has a rutile like structure where silicon is 6 coordinate. 
The density of stishovite is 4.287 g/cm3, which compares to α-quartz, the densest of the low pressure forms, which has a density of 2.648 g/cm3.
The difference in density can be ascribed to the increase in coordination as the six shortest Si-O bond lengths in stishovite (four Si-O bond lengths of 176 pm and two others of 181 pm) are greater than the Si-O bond length (161 pm) in α-quartz.
The change in the coordination increases the ionicity of the Si-O bond.
But more important is the observation that any deviations from these standard parameters constitute microstructural differences or variations which represent an approach to an amorphous, vitreous or glassy solid.
Note that the only stable form under normal conditions is α-quartz and this is the form in which crystalline silicon dioxide is usually encountered. 
In nature impurities in crystalline α-quartz can give rise to colors (see list).

Note also that both high temperature minerals, cristobalite and tridymite, have both a lower density and index of refraction than quartz. 
Since the composition is identical, the reason for the discrepancies must be in the increased spacing in the high temperature minerals. 
As is common with many substances, the higher the temperature the farther apart the atoms due to the increased vibration energy.
The high pressure minerals, seifertite, stishovite, and coesite, on the other hand, have a higher density and index of refraction when compared to quartz. 
This is probably due to the intense compression of the atoms that must occur during their formation, resulting in a more condensed structure.
Faujasite silica is another form of crystalline silica. 
It is obtained by dealumination of a low-sodium, ultra-stable Y zeolite with a combined acid and thermal treatment. 
The resulting product contains over 99% silica, has high crystallinity and high surface area (over 800 m2/g). 

Faujasite-silica has very high thermal and acid stability. 
For example, it maintains a high degree of long-range molecular order (or crystallinity) even after boiling in concentrated hydrochloric acid.
Molten silica exhibits several peculiar physical characteristics that are similar to the ones observed in liquid water: negative temperature expansion, density maximum, and a heat capacity minimum.
When molecular silicon monoxide, SiO, is condensed in an argon matrix cooled with helium along with oxygen atoms generated by microwave discharge, molecular SiO2 is produced which has a linear structure. 
Dimeric silicon dioxide, (SiO2)2 has been prepared by reacting O2 with matrix isolated dimeric silicon monoxide, (Si2O2). 
In dimeric silicon dioxide there are two oxygen atoms bridging between the silicon atoms with an Si-O-Si angle of 94° and bond length of 164.6 pm and the terminal Si-O bond length is 150.2 pm. 
The Si-O bond length is 148.3 pm which compares with the length of 161 pm in α-quartz. 
The bond energy is estimated at 621.7 kJ/mol.

Silica gel desiccant, indicating, <1% Cobalt chloride
Silica gel, -60-120 mesh, for column chromatography
Celpure(R) P100, meets USP/NF testing specifications
Celpure(R) P1000, meets USP/NF testing specifications
Celpure(R) P300, meets USP/NF testing specifications
Micro particles based on silicon dioxide, size: 0.5 mum
Micro particles based on silicon dioxide, size: 1.0 mum
Silica gel 60, 0.032-0.063mm (230-450 mesh)
Silica gel 60, 0.036-0.071mm (215-400 mesh)
Silica gel 60, 0.040-0.063mm (230-400 mesh)
Silica gel desiccant, indicating, -6+16 mesh granules
Silica gel, with moisture indicator (blue), -6-20 mesh
Silica, mesostructured, MSU-H (large pore 2D hexagonal)
Silica, mesostructured, SBA-15, 99% trace metals basis
Silica, standard solution, Specpure?, SiO2 1000?g/ml
Silicon Dioxide (Silica) Nanodispersion Type A (20nm)
Silicon Dioxide (Silica) Nanodispersion Type B (20nm)
Silicon dioxide, -325 mesh, 99.5% trace metals basis
Silicon dioxide, amorphous, hexamethyldisilazane treated
Silicon dioxide, washed and calcined, analytical reagent

In ceramics, SiO2 comes up when technicians talk about glaze chemistry. 
Silicon dioxide is an oxide contributed by many ceramic materials: all clays, feldspars and frits. 
Quartz or silica powder is almost 100% SiO2. 
But the SiO2 in quartz is something completely different than SiO2 in feldspar. 
In the latter Silicon dioxide is chemically combined with Al2O3 and KNaO.
Thus when technicians talk about silica they might be speaking of the mineral or the oxide. 
Silica, as a mineral, is composed of silicon dioxide (SiO2). 
In bodies SiO2 (as quartz mineral) will almost always exist as unmelted particles embedded in the fired matrix (although finer ones dissolve into the inter-particle glass). 
But in glaze chemistry we are talking about silica, the oxide. 
All glazes that melt completely and re-solidify contain SiO2, the oxide, many can be 70% or more. 
Materials yield their SiO2 to the glaze melt as kiln temperatures increase. 
Different materials dissolve into the melt at different temperatures. 
The particle size of materials affects the speed at which they dissolve in the melt. 
SiO2 is the principle glass former in glazes. 
SiO2 can bond with almost any other oxide and bring them into the glass structure.
-SiO2 is the principle, and often only glass forming oxide in glaze. 
Normally comprises more than 60% of most glazes and 70% of clays. 
Special purpose formulations which lack SiO2 often compromise structural stability and strength. 
Floating and container glass are more than 70% SiO2.
-Adjust this in relation to fluxes to regulate melting temperature and gloss.

Silica is refractory, Silicon dioxide melts at high temperatures, but Silicon dioxide is readily fluxed to melt lower. 
So its percentage regulates the glazes melting range.
-High SiO2 in relation to Al2O3 produces a glossy glaze (and vice versa). 
This is called the silica:alumina ratio.
-Increase Silicon dioxide at the expense of B2O3 to make glaze harder, more durable and brilliant. 
Boric oxide and silica can be interchanged to adjust glaze melting temperature.
-Decreasing SiO2 increases the melt fluidity; increasing Silicon dioxide raises the melting temperature, increases acid resistance, lowers expansion, increases hardness and gloss, and increases devitrification.
-Silicon dioxide is normal to use as much as possible in any glaze to keep expansion low, to prevent crazing, increase durability and resistance to leaching and enhance body/glaze fired strength. 
Note, however, that in certain boracic and feldspathic compositions Silicon dioxide can actually increase crazing so that other low expansion oxides may be needed to reduce glaze expansion.
-With boron and alumina, Silicon dioxide has the lowest expansion of all oxides.
-In clay bodies, quartz mineral particles act as a filler and behave as an aggregate, while chemically combined SiO2 in feldspar, kaolin, ball clay, etc., participates directly in the chemical reactions taking place to build silicate glasses. 
Thus the particle size of the parent material is often important in determining whether contributed silica affects the chemistry or participates simply as an aggregate in the fired matrix.

Silicon(IV) oxide, 15% in water, colloidal dispersion
Silicon(IV) oxide, 30% in water, colloidal dispersion
Silicon(IV) oxide, 50% in water, colloidal dispersion
Silicon(IV) oxide, amorphous fumed, S.A. 85-115m2/g
Zeolite - Mesoporous Silica Nanopowder (SBA-15 Type)
Chromosorb(R) W, AW-DMCS, 100-120 mesh particle size
Diatomaceous earth, calcined, filter aid, slightly calcined
Micro particles based on silicon dioxide, size: 0.15 mum
Silica gel, high-purity grade (15111), pore size 60 ??
Silica, mesoporous, 1 mum particle size, pore size ~2 nm
Silica, mesoporous, 1 mum particle size, pore size ~4 nm
Silica, mesoporous, 2 mum particle size, pore size ~2 nm
Silica, mesoporous, 2 mum particle size, pore size ~4 nm
Silica, mesoporous, 3 mum particle size, pore size ~2 nm
Silica, mesoporous, 3 mum particle size, pore size ~4 nm
Silica,fumed, hydrophilic, specific surface area 200 m2/g
Silica,fumed, hydrophilic, specific surface area 400 m2/g

When silicon dioxide SiO2 is cooled rapidly enough, it does not crystallize but solidifies as a glass. 
The glass transition temperature of pure SiO2 is about 1600 K (1330 °C or 2420 °F). 
Like most of the crystalline polymorphs the local atomic structure in pure silica glass is regular tetrahedra of oxygen atoms around silicon atoms. 
The difference between the glass and the crystals arises in the connectivity of these tetrahedral units. 
SiO2 glass consists of a non-repeating network of tetrahedra, where all the oxygen corners connect two neighbouring tetrahedra. 
Although there is no long range periodicity in the glassy network there remains significant ordering at length scales well beyond the SiO bond length. 
One example of this ordering is found in the preference of the network to form rings of 6-tetrahedra.

Silicon(IV) oxide, amorphous fumed, S.A. 175-225m?/g
Silicon(IV) oxide, amorphous fumed, S.A. 300-350m?/g
Silicon(IV) oxide, amorphous fumed, S.A. 350-420m2/g
UNII-2RF6EJ0M85 component VYPSYNLAJGMNEJ-UHFFFAOYSA-N
Amorphous silica: Vitreous silica, quartz glass, fused silica
Diatomaceous earth, flux-calcined, filter aid, flux calcined
LUDOX(R) AM colloidal silica, 30 wt. % suspension in H2O
LUDOX(R) CL colloidal silica, 30 wt. % suspension in H2O
LUDOX(R) CL-X colloidal silica, 45 wt. % suspension in H2O
LUDOX(R) LS colloidal silica, 30 wt. % suspension in H2O
LUDOX(R) SM colloidal silica, 30 wt. % suspension in H2O
LUDOX(R) TMA colloidal silica, 34 wt. % suspension in H2O
Silica gel orange, with moisture indicator free of heavy metals

Silica is manufactured in several forms including:
-glass (a colorless, high-purity form is called fused silica)
-synthetic amorphous silica
-silica gel (used e.g. as desiccants in new clothes and leather goods)
Silicon dioxide is used in the production of various products.
Inexpensive soda-lime glass is the most common and typically found in drinking glasses, bottles, and windows.
A raw material for many whiteware ceramics such as earthenware, stoneware and porcelain.
A raw material for the production of Portland cement.
A food additive, primarily as a flow agent in powdered foods, or to absorb water (see the ingredients list for).
The natural ("native") oxide coating that grows on silicon is hugely beneficial in microelectronics. 
Silicon dioxide is a superior electric insulator, possessing high chemical stability. 
In electrical applications, Silicon dioxide can protect the silicon, store charge, block current, and even act as a controlled pathway to allow small currents to flow through a device. 
At room temperature, however, Silicon dioxide grows extremely slowly, and so to manufacture such oxide layers on silicon, the traditional method has been the deliberate heating of silicon in high temperature furnaces within an oxygen ambient (thermal oxidation).
Raw material for aerogel in the Stardust spacecraft Used in the extraction of DNA and RNA due to its ability to bind to the nucleic acids under the presence of chaotropes.
Added to medicinal anti-foaming agent, like Simethicone, in a small proportion to enhance defoaming activity.
As hydrated silica in Toothpaste (abrasive to fight away plaque.)

Silica gel, high-purity grade, FIA according to DIN 51791
Silica, mesoporous, 0.5 mum particle size, pore size ~2 nm
Silica, mesoporous, 0.5 mum particle size, pore size ~4 nm
Silicon dioxide, acid washed and calcined, Analytical Reagent
Silicon dioxide, crystalline (fine), coating quality, >=99.9%
Chromosorb(R) P, NAW, 60-80 mesh particle size, bottle of 100 g
Chromosorb(R) W, AW, 80-100 mesh particle size, bottle of 100 g
Chromosorb(R) W, HP, 60-80 mesh particle size, bottle of 100 g
Diatomaceous earth, calcined, powder, suitable for most filtrations
LUDOX(R) AS-30 colloidal silica, 30 wt. % suspension in H2O
LUDOX(R) AS-40 colloidal silica, 40 wt. % suspension in H2O
LUDOX(R) HS-30 colloidal silica, 30 wt. % suspension in H2O
LUDOX(R) HS-40 colloidal silica, 40 wt. % suspension in H2O
LUDOX(R) TM-40 colloidal silica, 40 wt. % suspension in H2O
LUDOX(R) TM-50 colloidal silica, 50 wt. % suspension in H2O

Silicon dioxide is SiO2, also is known as silica, silicic acid or silicic acid anhydride. 
Silicon dioxides name is derived from the Latin Silex. 
The CAS number for silicon dioxide is 7631-86-9, and the most common form of silicon dioxide is quartz. 
Quartz makes up more than 10% of the Earth’s crust; it is also a major component of sand. 
Silicon dioxide is estimated that 95% of commercial silicon dioxide is used in the construction industry to make portland cement, though another use is for making glass—hydrated silica is even used in toothpaste to remove plaque.

Quartz Optical Window, 25.4mm (1.0in) dia x 1mm (0.04in) thick
Quartz Optical Window, 25.4mm (1.0in) dia x 2mm (0.08in) thick
Silica gel 60, 230 - 400 mesh, for flash column chromatography
Silica gel, Davisil(R) grade 22, pore size 60 ??, 60-200 mesh
Silica gel, high-purity grade, 60??, 35-60 mesh particle size
Silica gel, high-purity grade, pore size 60 ??, 70-230 mesh
Silica gel, HPLC grade, spherical, 3 micron APS, 120 angstroms
Silica gel, HPLC grade, spherical, 3 micron APS, 70 angstroms
Silica gel, technical grade (w/ fluorescent indicator), 60 F254
Silica gel, Type H, without binder, for thin layer chromatography
Silica gel, Type II, 3.5 mm bead size, Suitable for desiccation
Silica, fumed, powder, 0.2-0.3 mum avg. part. size (aggregate)
Silicon dioxide, for cleaning of platinum crucibles, calcined, crude
Silicon dioxide, fused (pieces), 4 mm, 99.99% trace metals basis
Silicon oxide, catalyst support, high surface area, S.A.250m2/g
Silicon(IV) Oxide, 99+%, 0.012 Micron (Fumed Colloidal Silica)


Synonyms: SILICA
Chemical Names:    SILICON DIOXIDE
CAS number: 7631-86-9
INS: 551
Functional Class:    
Food Additives
ANTICAKING_AGENT


Silicon(IV) oxide, 99.5% (metals basis) , -325 Mesh Powder
Zeolite - Mesoporous Silica Nanopowder (1D-Hexagonal SBA-41 Type)
Zeolite - Mesoporous Silica Nanopowder (3D-Cubic MCM-48 Type)
Celatom(R), acid-washed, for use in Total Dietary Fiber Assay, TDF-100A
Chromosorb(R) G, HP, 100-120 mesh particle size, bottle of 100 g
Chromosorb(R) P, AW-DMCS, 80-100 mesh particle size, bottle of 100 g
Chromosorb(R) W, AW, 100-120 mesh particle size, bottle of 100 g
Chromosorb(R) W, HP, 100-120 mesh particle size, bottle of 100 g
NBS 28 (silicon and oxygen isotopes in silica sand), NIST(R) RM 8546
Quartz disc, fused, 50.8mm (2.0in) dia x 1.59mm (0.06in) thick
Quartz disc, fused, 50.8mm (2.0in) dia x 3.18mm (0.13in) thick
Quartz disc, fused, 76.2 (3.0 in) dia x 3.18mm (0.13in) thick
Quartz disc, fused, 76.2mm (3.0in) dia x 1.59mm (0.06in) thick

Fused silica is a noncrystalline (glass) form of silicon dioxide (quartz, sand). 
Silicon dioxide lacks long range order in its atomic structure. 
Silicon dioxides highly cross linked three dimensional structure gives rise to it’s high use temperature, low thermal expansion coefficient, high purity, high transmission and high refractive index homogeneity.
This material is widely used in semiconductor, medical science, communications, lasers, infrared, electronics, measuring instruments, military, aerospace and others high-tech industry. 
NQW materials from the major manufacturers in all grades and specifications. 
All fused silica offered by NQW is certified by the manufacturers.

Quartz microscope slide, fused, 25.4x25.4x1.0mm (1.0x1.0x0.0394in)
Quartz microscope slide, fused, 50.8x25.4x1.0mm (2.0x1.0x0.0394in)
Quartz microscope slide, fused, 76.2x25.4x1.0mm (3.0x1.0x0.0394in)
Silica gel 60, 0.105-0.2mm (70-150 mesh), S.A. 500-600m2/g
Silica gel, high purity, 90??, 35-70 mesh, for column chromatography
Silica gel, high-purity grade (7734), pore size 60 ??, 70-230 mesh
Silica gel, high-purity grade (7754), pore size 60 ??, 70-230 mesh
Silica gel, high-purity grade, 40, >=400 mesh, for column chromatography
Silica gel, high-purity grade, 40, 35-70 mesh, for column chromatography
Silica gel, high-purity grade, 40, 70-230 mesh, for column chromatography
Silica gel, high-purity grade, 90??, 15-25 mum, for column chromatography
Silica gel, high-purity grade, pore size 40 ??, 35-70 mesh particle size
Silica gel, high-purity grade, pore size 60 ??, >=400 mesh particle size
Silica gel, technical grade, pore size 60 ??, 200-425 mesh particle size
Silica gel, technical grade, pore size 60 ??, 70-230 mesh, 63-200 mum
Silica, nanoparticles, mesoporous, 200 nm particle size, pore size 4 nm
Silicon dioxide, ~99%, 0.5-10 mum (approx. 80% between 1-5 mum)

Applications 
SiO2 (Silicon Dioxide or Silica) in its amorphous form is generally exploited in semiconductors to segregate conducting of differing areas.  
SiO2 has a high dielectric constant, mechanical resistance, and chemical selectivity.  
This selectivity makes it a good material in microelectronics and chromatography.  
Silicon Dioxide has been used in a wide range of applications such as resigns for separations, optical fibers, glasses, ceramics, and semiconductors.

Silicon dioxide, amorphous, cyclic azasilane/hexamethyldisilazane treated
Silicon dioxide, fused (granular), 4-20 mesh, 99.9% trace metals basis
Silicon Oxide Hollow NanospheresSilicon Dioxide Nanospheres Properties
Diatomaceous earth, flux-calcined, filter aid, flux calcined, treated with sodium carbonate
Diatomaceous earth, flux-calcined, filter aid, treated with sodium carbonate, calcined
Silica gel 60 ADAMANT(TM) on TLC plates, with fluorescence indicator 254 nm
Silica gel 60, 0.019-0.037mm (400-600 mesh), S.A. 500-600m2/g
Silica gel 60, 0.062-0.105mm (150-230 mesh), S.A. 500-600m2/g
Silica gel, Davisil(R) grade 710, pore size 50-76 ??, for thin layer chromatography
Silica gel, high-purity grade (10180), pore size 40 ??, 70-230 mesh particle size
Silica gel, high-purity grade (9385), pore size 60 ??, 230-400 mesh particle size
Silica gel, high-purity grade (Davisil Grade 12), pore size 22 ??, 28-200 mesh
Silica gel, high-purity grade (Davisil Grade 62), pore size 150 ??, 60-200 mesh
Silica gel, high-purity grade (Davisil Grade 635), pore size 60 ??, 60-100 mesh
Silica gel, high-purity grade (Davisil Grade 643), pore size 150 ??, 200-425 mesh
Silica gel, high-purity grade (Davisil Grade 646), 35-60 mesh, pore size 150 ??
Silica gel, high-purity grade (Davisil Grade 923), pore size 30 ??, 100-200 mesh

Synonym: Silica, Silicic anhydride, Silicon dioxide amorphous, Silicon dioxide, Amorphous silica
Formula: SiO2
CAS Number: 7631-86-9 
Formula Weight: 60.08 g/mol
Density: 2.196  g/cm³ at 25°C 
Melting Point: 1713°C
Color: white powder 
Solubility: Insoluble in water
Purity: 99.99% 4N (trace metal basis) 
Particle Size: <300 mesh

Silica gel, high-purity grade, 100??, 200-400 mesh, for preparative liquid chromatography
Silica gel, high-purity grade, 40??, 230-400 mesh, for preparative liquid chromatography
Silica gel, high-purity grade, 60??, gypsum ~13 %, for preparative liquid chromatography
Silica gel, high-purity grade, 90??, 70-230 mesh, for column chromatography
Silica gel, high-purity grade, for thin layer chromatography, H, without calcium sulfate
Silica gel, high-purity grade, pore size 60 ??, 130-270 mesh, for column chromatography
Silica gel, high-purity grade, pore size 60 ??, 200-400 mesh particle size
Silica gel, high-purity grade, Type G, 5-15 mum, for thin layer chromatography
Silica gel, preparative chromatography grade, spherical, 10 micron APS, 60 angstroms
Silica gel, preparative chromatography grade, spherical, 15 micron APS, 120 angstroms
Silica gel, preparative chromatography grade, spherical, 15 micron APS, 60 angstroms
Silica gel, preparative chromatography grade, spherical, 50 micron APS, 60 angstroms
Silica gel, preparative chromatography grade, spherical, 7.5 micron APS, 120 angstroms
Silica gel, wide pore, 150 angstroms, -100+200 Mesh, S.A. 350-400m2/g
Silica Nanosprings TM coated with zinc oxide and grown on fiber glass substrate (3.5 x 8cm)
Silica, mesoporous MCM-48, 15 mum particle size, pore size 3 nm, Cubic pore morphology
Silica, mesoporous SBA-16, <150 mum particle size, pore size 5 nm, Cubic pore morphology
Silica, nanopowder, spec. surface area 175-225 m2/g (BET), 99.8% trace metals basis
Silicon dioxide, nanopowder, 10-20 nm particle size (BET), 99.5% trace metals basis
Silicon(IV) oxide sputtering target, 50.8mm (2.0in) dia x 3.18mm (0.125in) thick
Silicon(IV) oxide sputtering target, 50.8mm (2.0in) dia x 6.35mm (0.250in) thick
Silicon(IV) oxide sputtering target, 76.2mm (3.0in) dia x 3.18mm (0.125in) thick
Silicon(IV) oxide sputtering target, 76.2mm (3.0in) dia x 6.35mm (0.250in) thick
Silicon(IV) oxide, 40% in water, colloidal dispersion, 0.02 micron particles
Silicon(IV) oxide, amorphous fumed, surface treated, S.A. 105-130m??/g, -325 mesh
Silicon(IV) oxide, amorphous fumed, surface treated, S.A. 105-145m??/g, -325 mesh
Silicon(IV) oxide, amorphous fumed, surface treated, S.A. 205-245m??/g, -325 mesh
Diatomaceous earth, flux-calcined, filter aid, acid washed, treated with sodium carbonate, flux calcined
Respirable alpha-quartz, NIST(R) SRM(R) 1878b, quantitative X-ray powder diffraction standard
Silica gel - technical grade, 230-400 mesh particle size, 40-63 |m particle size, pore size 60+

Silicon dioxide (SiO2), also know as silica, is a chemical compound which has many different crystalline forms and a wide range of applications. 
Silicon dioxide is used in everything from the production of widow glass and optical fibers to defoamers and cement. 
The term “Silicon Valley” was coined because of the use of silicon in the computer industry. 
Among its many uses, Silicon dioxide quite often appears as a flow agent or anti-caking agent in animal feeds and human foods.

Silica gel 60, with fluorescent indicator, 0.060-0.2mm (70-230 mesh), -70+230 Mesh Powder, S.A. 500-600m2/g
Silica gel, 30 mum particle size (average), average pore diameter 60 ??, Suitable for normal-phase adsorption-partition chromatography
Silica gel, EMD Millipore, TLC grade (11695), 15 mum, pore size 60 ??, with silica/alumina binder
Silica gel, high-purity grade (7749), with gypsum binder and fluorescent indicator, for thin layer chromatography
Silica gel, high-purity grade (Davisil Grade 633), pore size 60 ??, 200-425 mesh particle size
Silica gel, high-purity grade (Davisil Grade 636), pore size 60 ??, 35-60 mesh particle size
Silica gel, high-purity grade (puriss), pore size 60 ??, 70-230 mesh, for column chromatography
Silica gel, high-purity grade (w/ Ca, ~0.1%), pore size 60 ??, 230-400 mesh particle size
Silica gel, high-purity grade, HF254, without calcium sulfate, with fluorescent indicator, for thin layer chromatography
Silica gel, high-purity grade, pore size 60 ??, 2-25 mum particle size, without binder, pore volume 0.75 cm3/g, for thin layer chromatography
Silica gel, high-purity grade, pore size 60 ??, 2-25 mum particle size, without binder, with fluorescent indicator, pore volume 0.75 cm3/g, for thin layer chromatography
Silica gel, high-purity grade, pore size 60 ??, 220-440 mesh particle size, 35-75 mum particle size, for flash chromatography
Silica gel, high-purity grade, pore size 60 ??, 230-400 mesh particle size, 40-63 mum particle size, for flash chromatography
Silica gel, high-purity grade, pore size 60 ??, 5-25 mum particle size, without binder, for thin layer chromatography
Silica gel, high-purity grade, pore size 60 ??, 70-230 mesh, 63-200 mum, for column chromatography

Quality Level: 100
form: solid
quality: acid washed
impurities:
≤0.01% in acid soluble iron (Fe)
≤0.5% soluble in HCl
loss: ≤0.5% loss on ignition, 800 °C
refractive index: n20/D 1.544 (lit.)
mp: 1610 °C (lit.)
density: 2.6 g/mL at 25 °C (lit.)
anion traces: chloride (Cl-): ≤100 mg/kg
SMILES string: O=[Si]=O
InChI: 1S/O2Si/c1-3-2
InChI key: VYPSYNLAJGMNEJ-UHFFFAOYSA-N

Silica gel, high-purity grade, Type G, with ~13% calcium sulfate, for thin layer chromatography
Silica gel, high-purity grade, with ~15% calcium sulfate and fluorescent indicator, GF254, for thin layer chromatography
Silica gel, HPLC grade, spherical, 2.2 micron APS, 120 angstroms, 99.99+% , S.A. 340m2/g, P.V. 1.00cc/g
Silica gel, HPLC grade, spherical, 2.2 micron APS, 80 angstroms, 99.99+% , S.A. 470m2/g, P.V. 0.95cc/g
Silica gel, HPLC grade, spherical, 3 micron APS, 260 angstroms, 99.99+%, S.A. 130m2/g, P.V. 0.90cc/g
Silica gel, HPLC grade, spherical, 5 micron APS, 120 angstroms, 99.99+% , S.A. 340m2/g, P.V. 1.00cc/g
Silica gel, HPLC grade, spherical, 5 micron APS, 260 angstroms, 99.99+% , S.A. 150m2/g, P.V. 0.90cc/g
Silica gel, HPLC grade, spherical, 5 micron APS, 70 angstroms, 99.99+% , S.A. 500m2/g, P.V. 0.95cc/g
Silica gel, HPLC/UHPLC grade, spherical, 1.6 micron APS, 110 angstroms, 99.99+%, S.A. 340m2/g, P.V. 0.95cc/g
Silica gel, preparative chromatography grade, spherical, 20 micron APS, 100 angstroms, 99.99+% , S.A. 335m2/g, P.V. 1.00cc/g
Silica gel, preparative chromatography grade, spherical, 20 micron APS, 150 angstroms, 99.99+%, S.A. 270m2/g, P.V. 1.00cc/g
Silica gel, preparative chromatography grade, spherical, 20 micron APS, 80 angstroms, 99.99+% , S.A. 515m2/g, P.V. 1.00cc/g
Silica gel, technical grade (w/ Ca, ~0.1%), 60??, 230-400 mesh particle size, Ca 0.1-0.3 %
Silica gel, technical grade, pore size 60 ??, 230-400 mesh particle size, 40-63 mum particle size

Silicon Dioxide Powder is vital because its porous structure allows it to absorb moisture and prevent clumping and binding of ingredients, with which it is combined. 
From flour for baking and cereal mixes to home-made seasoning and spice blends, Silicon Dioxide is a “magic powder” that can improve the quality of all your projects. 
Why search any further for this hard-to-find item? Our customers agree that American Spice Company can deliver exactly what you need with the best customer service. 
Stock up on Silicon Dioxide today.

Silica gel, TLC high purity grade, with gypsum binder and fluorescent indicator, 12 Micron APS, S.A. 500-600m2/g, 60?, pH 6.5-7.5
Silica gel, TLC high purity grade, with gypsum binder, 12 Micron APS, S.A. 500-600m2/g, 60?, pH 6-7
Silica gel, TLC high purity grade, without binder, 12 Micron APS, S.A. 500-600m2/g, 60, pH 6.5-7.5
Silica gel, TLC high purity grade, without binder, with fluorescent indicator, 12 Micron APS, S.A. 500-600m2/g, 60?, pH 6.5-7.5
Silica gel, TLC high-purity grade, 5-25 mum, pore size 60 ??, with gypsum binder and fluorescent indicator, pore volume 0.75 cm3/g
Silica, mesoporous SBA-15, <150 mum particle size, pore size 4 nm, Hexagonal pore morphology
Silica, mesoporous SBA-15, <150 mum particle size, pore size 6 nm, Hexagonal pore morphology
Silica, mesoporous SBA-15, <150 mum particle size, pore size 8 nm, Hexagonal pore morphology
Silicon dioxide, nanopowder (spherical, porous), 5-15 nm particle size (TEM), 99.5% trace metals basis
Silicon dioxide, single crystal substrate, optical grade, 99.99% trace metals basis, &#60;0001&#62;, L x W x thickness 10 mm x 10 mm x 0.5 mm
Silicon oxide, catalyst support, high surface area, S.A.160m2/g, total pore volume 0.5cc/g, pore size 100 and 1000 angstrom
Silicon(IV) oxide, 40% in water, colloidal dispersion, 0.02 micron particles, S.A. 200m 2/g

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