SILICON DIOXIDE

Silicon dioxide is used stone, plaster, cement, glass or ceramics (eg dishes, pots/pans, food storage containers, construction and insulation materials), plastic (eg food packaging and storage, toys, mobile) and wood (eg floors, furniture) , toys) can be found in products with the material.
Silicon dioxide is used in hydraulic fluids in automotive suspension, lubricants in engine oil, brake fluids, coolants in refrigerators and oil-based electric heaters.
Silicon dioxide used as an ingredient may be labeled as silica, silicon dioxide, synthetic amorphous silica (SAS), or E551.

CAS Number: 7631-86-9 
EC Number: 231-545-4
E Number: E551 (acidity regulators, ...)
MDL Number: MFCD00011232
Molecular Formula: O2Si
Molar Mass: 60.08 g/mol

SYNONYMS:
Silicon dioxide, Quartz, Silica, Silicic oxide, Silicon(IV) oxide, Crystalline silica, Pure Silica, Silicea, Silica sand, Silica, Quartz, Aerosil, acticel, cab-o-sil, Quartz sand, Fumed silica, cab-o-sperse, Silica, fused, MATTING AGENT, flatting agent, Silicon dioxide, flatting agents, Amorphous silica, Silica, vitreous, delustering agent, Quartz-beta (SiO2) (9CI), Aerosil, White carbon, NEOSYL, Hollow glass microspheres, silica,amorphous, amorphoussilica(silicondioxide), SILICA GEL 60 PF254 FOR PREPARATIVE LAYE, Dioxosilane, Geduran Si 60, Porous Silica, SILICON DIOXIDE, Silica, Dioxosilane, 7631-86-9, Silicic anhydride, Diatomaceous silica, Wessalon, Zorbax sil, Silica, amorphous, Silica, colloidal, Sillikolloid, Extrusil, Santocel, Sipernat, Acticel, Carplex, Neosil, Neosyl, Porasil, Silikil, Siloxid, Zipax, colloidal silica, White carbon, Silicone dioxide, Cab-o-sil M-5, Vulkasil S, Snowtex O, Corasil II, Tokusil TPLM, Dri-Die, Manosil vn 3, Ultrasil VH 3, Ultrasil VN 3, Carplex 30, Carplex 80, Snowtex 30, Zeofree 80, Aerosil K 7, Min-U-Sil, Syton 2X, Positive sol 232, Aerogel 200, Aerosil 300, Aerosil 380, Amorphous silica dust, Ludox hs 40, Silanox 101, Vitasil 220, Positive sol 130M, Silicon dioxide (amorphous), Aerosil A 300, Aerosil E 300, Silicon dioxide, fumed, Nalfloc N 1050, Quso 51, Quso G 30, Aerosil 200, Sg-67, ETJ7Z6XBU4, HK 400, CI 7811, DTXSID1029677, CHEBI:30563, U 333, INS NO.551, INS-551, E-551, Precipitated amorphous silica, Sandstone, Silicea, Silica marina, Naturasil Scars, Olea Olidental, Super-cel, Fire Agate, Red Jasper, Red Quartz, Tigers Eye, Chrysolith 6X, Dioxide, Silicon, Silicea 3X, Silicea 6X, Dental type silica, Honest-Paste Kids, Quartz 8, Silicea 12X, Silicea 30C, Silicea 30X, Aventurine 8101, Chrysoprase 8113, Quartz 30, Sandstone 8144, Aerosil 130, HAIRBALLS, Silicea 200C, Silicea 200X, SKIN ERUPTIONS, Syloid 244, 380, Aerosil, Carneol 8109, Citrine 8114, Fire Agate 8116, Red Jasper 8138, Red Quartz 8139, Silicea 8012, Tigers Eye 8152, Rose Quartz 8142, Quso G32, Naturasil Stretch Marks, RefChem:6681, Cab-O-Sil M-5P, Silica 6 Special Order, SILICEA 200ck, G32, Quso, Quso F-22, Quso G 32, silica (silicon dioxide), OPRECARE 12, OPRECARE 24, TONICPET 12, Jasper 17 Special Order, Quartz 60 Special Order, Silica 20 Special Order, Silica 30 Special Order, 28TAK DOUX TOOTH, SCAR REMOVAL SHEETS, Silicea Organic Cane Sugar, TOOTH NOTE AQUA MINT, 2080 Dentistry Night Fresh, Fruity Scrub Body Exfoliation, PHYENLIMCIDE TOOTHPASTE, Rxhomeo Homeopathic Combo 21, 2080 Dentistry Night Repair, Dr. Zenni Kids tooth (Baby), DTXCID009677, Cinis comp A 21 Special Order, Nekvnro SCAR REMOVAL SHEETS, Jacksons Cell Salts SILICA 6X, TOOTH NOTE PINEAPPLE MINT, Bestmade Natural Products Silicea, Cinis comp. CI 6 Special Order, FRESH MINT TEETH WHITENING, Jacksons Cell Salts SILICA 6X 12, Chlorine Dioxide Air Sterilization Card, EVERTOX SPECIAL BATH PREPARATIONS, OPRECARE 3SET (07,12,21), SONATURAL ALL KILL BLACKHEAD CLEAR, Sodium Monofluorophosphate, Silicon Dioxide, Dr. Zenni GGOGGOMA ToothpasteVanilla flavor, Dr. Zenni GGOGGOMA ToothpasteRaspberry flavor, Bestmade Natural Products Silicea 6x Lactose-free, 231-545-4, 601-214-2, 643-045-7, 685-393-2, 807-338-5, 921-597-2

Silicon dioxide occurs almost everywhere on earth.
Silicon dioxide is one of the most important and abundant oxides on earth, constituting about 60% weight of the earth’s crust as silica itself or in combination with other metal oxides in silicates.
Silicon dioxide is commonly found as sand in the vast ocean and river shores, their beds, deserts, rocks, and minerals.

Silicon dioxide exists in several structural forms: polymorphic crystalline silica, synthetic quartz crystals, amorphous silica, and vitreous silica.
This classification is not complete as there are other forms of silica synthesized for specialized applications.
Silicon dioxide is also known as silicone dioxide.

Silicon dioxide has a variety of applications: to control a product’s viscosity, add bulk, and reduce a formulation’s transparency.
Silicon dioxide can also function as an abrasive.
In addition, Silicon dioxide can act as a carrier for emollients, and may be used to improve a formulation’s skin feel.

Spherical Silicon dioxide is porous and highly absorbent, with absorption capabilities roughly 1.5 times its weight.
A typical claim associated with Silicon dioxide is oil control.
Silicon dioxide is a silicon oxide made up of linear triatomic molecules in which a silicon atom is covalently bonded to two oxygens.

Silicon dioxide contains sodium stabilizing counterion
Silica is silicon dioxide, one of the most abundant materials on the earth's crust.
Quartz is an example of silica.

Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO2, and is commonly found in nature as quartz.
In many parts of the world, Silicon dioxide is the major constituent of sand.
Silicon dioxide is one of the most complex and abundant families of materials, existing as a compound of several minerals and as a synthetic product.

Examples include fused quartz, fumed silica, opal, and aerogels.
Silicon dioxide is used in structural materials, microelectronics, and as components in the food and pharmaceutical industries.
All forms are white or colorless, although impure samples can be colored or opaque.

Silicon dioxide is a common fundamental constituent of glass.
Silicon dioxide is a silicon oxide made up of linear triatomic molecules in which a silicon atom is covalently bonded to two oxygens.
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.
Silicon Dioxide is a natural compound of silicon and oxygen found mostly in sand, Silica has three main crystalline varieties: quartz, tridymite, and cristobalite.
Fine particulate silica dust from quartz rock causes over a long-term progressive lung injury, silicosis.

Silicon dioxide (SiO₂) is a compound composed of two elements: silicon (Si) and oxygen (O).
Silicon dioxide, also known as silica or SiO2, is a naturally occurring compound.
Silicon dioxide's made of silicon and oxygen.

Both elements are abundant on our planet.
If you've held a rock or touched sand, you've encountered silicon dioxide.
In fact, our bodies use Silicon dioxide to support the development of our bones, connective tissues, and more.

Silicon Dioxide is a natural compound, also commonly known as silica.
Silicon dioxide is an oxide of silicon.
The chemical formula of Silicon Dioxide is SiO2.

This means Silicon dioxide consists of silicon (Si) and oxygen (O2).
Silica has a water solubility of 0.12 g/L, meaning its solubility isn’t particularly high.
Silicon dioxide has a high melting point which makes it useful in a wide range of applications.

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.
It makes up more than 95 percent of known rocks on the planet.
When you sit on a beach, it’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 it’s unclear what role Silicon dioxide plays, it’s thought to be an essential nutrient our bodies need.
Silicon dioxide, also called silica, is a compound of silicon and oxygen with the chemical formula SiO₂.

Silicon dioxide's building block is the silica tetrahedron: a single silicon atom bonded to four oxygen atoms (SiO₄).
These tetrahedra link by sharing their corner oxygen atoms — each oxygen bridges two silicon atoms — to build up an extended three-dimensional framework.
That simple, strongly bonded unit is what every form of silica has in common, from a grain of beach sand to a pane of window glass to the anti-caking powder in your spice jar.

Silicon dioxide is abundant in nature, mainly as the mineral quartz, which is a major component of sand, sandstone and granite.
Because of its strong silicon–oxygen bonds, silicon dioxide is chemically stable and largely inert — it resists most acids (hydrofluoric acid is the notable exception), does not react with water under ordinary conditions, and is stable to high temperatures.

What changes between one type of silica and another is not the chemistry but the structure and particle size, and those differences turn out to matter a great deal.
With boron and alumina, Silicon dioxide has the lowest expansion of all oxides.
Silicon dioxide (SiO₂) is a compound commonly found in nature.

Sand is the basic component of minerals such as quartz and has a very hard structure.
Usually 'silica ', also known as Silicon dioxide.
Silicon dioxide is used in industry in glass production, ceramic making, and electronic materials.

Silicon dioxide is also used as an additive in foods, especially as an anti-caking agent.
Silicon dioxide can occur naturally in amorphous or crystalline form, and its best-known crystal form is quartz.
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, Silicon dioxide is the major constituent of sand.
Silicon dioxide 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, opal and aerogels.

Silicon dioxide (SiO2), also known 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.
When many people think about silicon dioxide, they likely think of the natural material we commonly refer to as sand.
However, silicon dioxide doesn’t just come from a beach.

In its nonsynthetic form, Silicon dioxide is commonly known as quartz, which is one of the most abundant minerals on the earth’s surface, and is a significant component of many different types of rocks.
Silicon dioxide can also be produced synthetically through a variety of methods.

Therefore, before silicon dioxide can be used in a feed for organic livestock, it must be determined whether or not the silicon dioxide is synthetic.
Only nonsynthetic, mined mineral versions of silicon dioxide are allowed to be used in feed for organic livestock.
Silicon dioxide (SiO₂), commonly known as silica, is one of the most abundant inorganic compounds found naturally in the Earth's crust and is also produced synthetically for numerous industrial applications.

Silicon dioxide exists in both crystalline and amorphous forms, each exhibiting distinct physical properties and application profiles.
Silicon dioxide is highly valued for its exceptional thermal stability, chemical inertness, mechanical strength, optical transparency, and electrical insulating properties.
These characteristics make Silicon dioxide one of the most versatile inorganic materials used across a wide range of industries.

Synthetic amorphous Silicon dioxide is extensively utilized as a reinforcing filler, thickening agent, anti-caking agent, polishing agent, matting agent, adsorbent, carrier, desiccant, and rheology modifier.

Crystalline Silicon dioxide, primarily quartz, is widely used in glass manufacturing, ceramics, construction materials, and foundry applications.
Due to its outstanding durability and stability, silicon dioxide is employed in coatings, paints, plastics, rubber, pharmaceuticals, cosmetics, food processing, electronics, semiconductors, catalysts, chromatography, water treatment, and numerous advanced engineering applications.

USES and APPLICATIONS of SILICON DIOXIDE:
Silicon dioxide is widely used in coating products, inks and toners, adhesives and sealants, lacquers, putties, plasters, modeling clay, cosmetics and personal care products, washing and cleaning products, and pharmaceuticals.
Silicon dioxide is used stone, plaster, cement, glass or ceramics (eg dishes, pots/pans, food storage containers, construction and insulation materials), plastic (eg food packaging and storage, toys, mobile) and wood (eg floors, furniture) , toys) can be found in products with the material.

Silicon dioxide is used in hydraulic fluids in automotive suspension, lubricants in engine oil, brake fluids, coolants in refrigerators and oil-based electric heaters.
Silicon dioxide used as an ingredient may be labeled as silica, silicon dioxide, synthetic amorphous silica (SAS), or E551.
Silicon dioxide has many uses.

For example, construction industries rely heavily on Silicon dioxide, to create cement products.
Currently, this makes up the majority of Silicon dioxide's usage.
But don’t let that mislead you.

Silicon dioxide is also widely found in most life science industries.
Examples are food and feed products, as well as cosmetics and pharmaceutical articles.

In all of these industries, Silicon dioxide serves as an anti-caking agent.
This means Silicon dioxide helps to avoid clumping.
When humidity finds Silicon dioxide's way into the packaging, clumping will occur between powdered ingredients.

Products will stick together, leading to difficult dispersal.
Anti-caking agents like silicon dioxide help to prevent this clumping.
They do this by absorbing water, keeping the other ingredients dry.

Silicon dioxide is one of the most widely used industrial minerals and serves as an essential raw material in the production of glass, fiberglass, optical fibers, ceramic products, refractories, cement, concrete, engineered stone, and construction materials because of its exceptional thermal stability and mechanical strength
In the coatings industry, silicon dioxide functions as a matting agent, anti-settling additive, rheology modifier, anti-sagging agent, and scratch-resistant filler in architectural paints, industrial coatings, automotive finishes, powder coatings, wood coatings, and protective surface treatments.

Silicon Dioxide is extensively incorporated into rubber compounds and tire manufacturing as a reinforcing filler, improving tensile strength, abrasion resistance, rolling resistance, wet traction, durability, and fuel efficiency of modern high-performance tires.
Silicon dioxide is widely utilized in plastics and polymer composites where it enhances stiffness, dimensional stability, thermal resistance, wear resistance, and mechanical performance while reducing shrinkage during processing.

In adhesives and sealants, Silicon Dioxide serves as a thickening agent, viscosity modifier, anti-settling additive, and reinforcing filler that improves mechanical strength, application properties, and long-term durability.
Silicon Dioxide is extensively employed in the pharmaceutical industry as a glidant, anti-caking agent, tablet flow enhancer, carrier, stabilizer, and moisture-control additive during the manufacture of tablets, capsules, powders, and granulated formulations.

Within the cosmetics and personal care industry, silicon dioxide functions as an absorbent, anti-caking agent, viscosity modifier, bulking agent, soft-focus additive, and oil-control ingredient in facial powders, foundations, creams, lotions, toothpaste, deodorants, and skincare formulations.
The food industry utilizes amorphous silicon dioxide as an anti-caking agent (E551) to improve powder flowability, prevent moisture-induced agglomeration, and extend shelf life in seasonings, powdered beverages, dairy products, spices, coffee creamers, salt, and nutritional supplements.

In electronics and semiconductor manufacturing, ultra-high-purity silicon dioxide is indispensable as a dielectric insulator, passivation layer, gate oxide material, diffusion barrier, and substrate component in integrated circuits, microprocessors, sensors, and photovoltaic devices.
Silicon dioxide also plays an important role in chromatography, catalyst supports, filtration systems, water purification, chemical processing, agriculture, oil and gas drilling fluids, precision polishing, abrasives, paper manufacturing, textile processing, printing inks, battery technologies, advanced ceramics, aerospace materials, and numerous nanotechnology applications.

Silicon dioxide is found in sunscreens, scrubs, and wide range of other skin care, makeup, and hair care preparations.
Silicon dioxide has been successfully used in hypoallergenic and allergy-tested formulations.
Uses of Silicon dioxide: Functionalized RAFT agent for controlled radical polymerization; especially suited for the polymerization of styrene; acrylate and acrylamide monomers.

Azide group can be used to conjugate to a variety of alkyne-functionalized biomolecules.
Silicon dioxide is used as a chain Transfer Agent (CTA).
Uses of Silicon dioxide: manufacture of glass, water glass, refractories, abrasives, ceramics, enamels; decolorizing and purifying oils, petroleum products, etc.; in scouring- and grinding-compounds, ferrosilicon, molds for castings; as anticaking and defoaming agent.

Silicon dioxide is used as a filler in fertilizers, and also, in the manufacture of glass, ceramics, abrasives, rubber and cosmetics.
In powdered food products and pharmaceutical tablets, silicon dioxide is added as a flow agent to absorb water.
Silicon dioxide is also used as a wine, beer, and juice fining agent or stabilizer.
In ceramics, Silicon dioxide 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% Silicon dioxide.
But the Silicon dioxide 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 Silicon dioxide, they might be speaking of the mineral or the oxide.
Silica, as a mineral, is composed of silicon dioxide (SiO2).

In bodies, Silicon dioxide (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 Silicon dioxide, the oxide.

All glazes that melt completely and re-solidify contain SiO2, the oxide.
Many can be 70% or more.
Materials yield their Silicon dioxide 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.
Silicon dioxide is the principle glass former in glazes.

Silicon dioxide can bond with almost any other oxide and bring them into the glass structure.
Decreasing Silicon dioxide increases the melt fluidity; increasing it raises the melting temperature, increases acid resistance, lowers expansion, increases hardness and gloss, and increases devitrification.

In addition to being used to enhance regular foods, silicon dioxide is added to nutritional supplements and has industrial uses.
Similar to food uses, silicon dioxide is included in dietary supplements to improve their stability and consistency.
Dietary supplements comprise more than half of the products containing silicon dioxide.

Products include capsule, tablet, liquid, chewable, and syrup form supplements.
Industrial production also uses silicon dioxide.
Naturally found in quartz, sand, and rocks, manufacturers use it to make glass and concrete, making it a crucial part of the construction industry.

Crystalline silicon dioxide is the type most commonly associated with industrial uses.
Silicon dioxide is used in structural materials, microelectronics (as an electrical insulator), and as components in the food and pharmaceutical industries.

-Understanding Safe Uses of Silicon Dioxide: 
Silicon dioxide, also known as silica, naturally occurs in minerals, some plants, and grains.
Silicon dioxide's chemical formula, SiO2, consists of silicon and oxygen.

-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.

-In clay bodies, quartz mineral particles act as a filler and behave as an aggregate, while chemically combined Silicon dioxide 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 dioxide 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 Silicon dioxide often compromise structural stability and strength.
Floating and container glass are more than 70% Silicon dioxide.

-Adjust this in relation to fluxes to regulate melting temperature and gloss.
Silicon dioxide is refractory, it melts at high temperatures, but it is readily fluxed to melt lower.
So Silicon dioxide's percentage regulates the glazes melting range.

-High Silicon dioxide in relation to Al2O3 produces a glossy glaze (and vice versa).
This is called the Silicon dioxide:alumina ratio.

-Increase Silicon dioxide at the expense of B2O3 to make glaze harder, more durable and brilliant.
Boric oxide and Silicon dioxide can be interchanged to adjust glaze melting temperature.

-Uses of Silicon dioxide: 
SDS mixture of sodium alkyl sulfates consisting chiefly of sodium lauryl sulfate
Silicon dioxide is mined from deposits of diatomaceous soft chalk-like rock (keiselghur).
This is an important group of extender pigments, which is used in a variety of particle sizes.
They are used as a flatting agent to reduce gloss of clear coatings and to impart shear thinning flow properties to coatings.
They are relatively expensive.

-Uses of Silicon dioxide:
Silicon(IV) oxide, amorphous is used as carriers, processing aids, anti-caking and free-flow agents in animal feed.
Defoamer applications such as paint, food, paper, textile and other industrial applications.
Synthetic silicon dioxides are used as a rheology control agent in plastics.
Silicon dioxide is also used to manufacture adhesives, sealants and silicones.

-Semiconductors use of Silicon dioxide:
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 and as a second 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 dioxide 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.
Silicon dioxide films preserve the electrical characteristics of p–n junctions and prevent these electrical characteristics from deteriorating by the gaseous ambient environment.

Silicon dioxide 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).

-Structural use of Silicon dioxide:
About 95% of the commercial use of Silicon dioxide (sand) is in the construction industry, e.g. in 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 Silicon dioxide 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.

-Precursor to glass and silicon:
Silicon dioxide 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 Silicon dioxide 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 centres.

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 telecommunications 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+2C⟶Si+2CO

-Food, cosmetic, and pharmaceutical applications of Silicon dioxide:
Silicon dioxide, 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, Silicon dioxide is useful for its light-diffusing properties and natural absorbency.

Diatomaceous earth, a mined product, Silicon dioxide 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.

WHY IS SILICON DIOXIDE USED IN FOOD?
Silicon dioxide, a major component of glass, is also used in the food industry as a food additive.
You might wonder: can Silicon dioxide really be eaten?

The answer lies in Silicon dioxide's specific functions.
First, silicon dioxide is an excellent anti-caking agent, preventing powdered or granular foods from clumping during storage and transportation.

Second, Silicon dioxide improves the flowability of powders and granules, making food processing and production more efficient.
In addition, appropriate amounts of silicon dioxide can improve texture, making food smoother and more uniform.

Silicon dioxide also has mild moisture-absorbing properties, helping foods maintain suitable humidity and extending shelf life—almost like providing a “constant-humidity environment” that preserves flavor and quality.
Of course, despite its wide use, silicon dioxide must comply with relevant regulations and standards.

Only when used within safe limits can food quality and safety be ensured.
While enjoying food, Silicon dioxide is always wise to pay attention to ingredients and practice healthy, informed eating.

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.”

BENEFITS of SILICON DIOXIDE:
Silicon dioxide improves the mechanical strength, hardness, and durability of numerous industrial products.
Silicon Dioxide's excellent reinforcing properties significantly enhance the performance of rubber compounds, plastics, coatings, adhesives, and sealants.
Silicon Dioxide provides superior scratch and abrasion resistance in coatings, paints, and surface finishes.

Silicon Dioxide's outstanding thermal stability enables reliable performance under extreme processing temperatures.
High chemical resistance minimizes degradation in aggressive chemical environments.
Silicon Dioxideenhances rheological control and suspension stability in liquid formulations.

Silicon Dioxide's excellent adsorption properties allow efficient moisture control, impurity removal, and catalyst support applications.
Silicon dioxide contributes to improved dimensional stability and reduced thermal expansion in engineering materials.
Its electrical insulation properties make Silicon Dioxide indispensable in semiconductor manufacturing and electronic devices.
Silicon Dioxide supports the production of environmentally durable products with long service life and minimal maintenance requirements.

TECHNICAL INFORMATION of SILICON DIOXIDE:
Silicon dioxide exists in both natural and synthetic forms, each optimized for different industrial applications. Synthetic amorphous silica is manufactured using precipitation, pyrogenic (fumed), gel, or colloidal processes that allow precise control over particle size, porosity, surface area, and rheological behavior.
Surface-treated silica grades are available to improve compatibility with hydrophobic resin systems, reduce moisture adsorption, enhance dispersion, and optimize processing characteristics.
The outstanding combination of thermal stability, chemical inertness, mechanical reinforcement, optical performance, electrical insulation, and adsorption capacity has established silicon dioxide as one of the most versatile functional materials in modern industrial technology.

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 Silicon dioxide 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, Silicon dioxide has a small particle size, high specific surface area, and gelling and thickening abilities.

Something else that makes silica unique is Silicon dioxide's solubility.
Silicon dioxide is not soluble in either water or organic solvents.
In addition to being used in food supplements and cosmetics, Silicon dioxide 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, Silicon dioxide might also change the material is absorbed and excreted in the human body.
Silicon dioxide is a natural compound of silicon and oxygen mostly found in sand, Silica has three main types of crystals: quartz, tridymite and cristobalite.
Silicon dioxide is a silicon oxide composed of linear triatomic molecules in which one silicon atom is covalently bonded to two oxygens.

PRODUCTION of SILICON DIOXIDE:
***LABORATORY OR SPECIAL METHODS
From Organosilicon Compounds
Many routes to silicon dioxide start with an organosilicon compound, e.g., HMDSO, TEOS.
Synthesis of silica is illustrated below using tetraethyl orthosilicate (TEOS).
Simply heating TEOS at 680–730 °C results in the oxide:
Si(OC₂H₅)₄ → SiO₂ + 2 O(C₂H₅)₂

Similarly, TEOS combusts around 400 °C:
Si(OC₂H₅)₄ + 12 O₂ → SiO₂ + 10 H₂O + 8 CO₂
TEOS undergoes hydrolysis via the so-called sol-gel process.
The course of the reaction and nature of the product are affected by catalysts, but the idealized equation is:
Si(OC₂H₅)₄ + 2 H₂O → SiO₂ + 4 HOCH₂CH₃

***OTHER METHODS
Being highly stable, silicon dioxide arises from many methods.
Conceptually simple, but of little practical value, combustion of silane gives silicon dioxide.
This reaction is analogous to the combustion of methane:
SiH₄ + 2 O₂ → SiO₂ + 2 H₂O
However, the chemical vapor deposition of silicon dioxide onto crystal surfaces from silane has been used using nitrogen as a carrier gas at 200–500 °C.

HOW IS SILICON DIOXIDE USED IN FOOD?
The food industry uses silicon dioxide as a food additive.
Its primary purpose is to improve the quality and stability of products.
Silicon dioxide does this by preventing clumping and caking and improving the flow of products.

Foods that contain silicon dioxide include:
Beer
Spices
Dehydrated soups
Protein powders
Baking powders
Instant coffee
Processed cheese
Vegetable oil
Dry cereals
Chewing gum
Syrup
Some plant foods, like barley, oats, wheat, rice, herbaceous plants, carrots, potatoes, green beans, apples, and bananas, naturally contain silicon dioxide.

CHEMICAL PROPERTIES of SILICON DIOXIDE:
Silicon dioxide is a white crystal or powder
Diatomaceous earth is a transparent to gray, odorless amorphous powder.
Amorphous silica, the noncrystalline form of SiO2, is a transparent to gray, odorless, amorphous powder

PHYSICAL PROPERTIES of SILICON DIOXIDE:
Silicon dioxide is a colorless amorphous (i.e., fused silica) or crystalline (i.e., quartz) material having a low thermal expansion coefficient and excellent optical transmittance in far UV.
Silicon dioxide is insoluble in strong mineral acids and alkalis except HF, concentrated H3PO4, NH4 HF2, concentrated alkali metal hydroxides.
Owing to its good corrosion resistance to liquid metals such as Si, Ge, Sn, Pb, Ga, In, Tl, Rb, Bi, and Cd, Silicon dioxide is used as crucible container for melting these metals, while silica is readily attacked in an inert atmosphere by molten metals such as Li, Na, K Mg, and Al.
Quartz crystals are piezoelectric and pyroelectric.
Maximum service temperature of Silicon dioxide is 1090°C.

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 Silicon dioxide, 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.

BASIC PROPERTIES OF SILICON DIOXIDE:
PHYSICAL PROPERTIES
High melting point and boiling point: 
Silicon dioxide has a melting point of 1713 °C and a boiling point of 2230 °C, giving it outstanding thermal stability.

High hardness: 
Silicon dioxide is very hard and is a major component of natural quartz.

Moderate density: 
With a density of about 2.2 g/cm³, Silicon dioxide has a stable structure while remaining relatively lightweight, which is beneficial for processing and applications.

High corrosion resistance: 
Silicon dioxide is resistant to most acids, bases, and other chemical substances.

High transparency: 
Its excellent light transparency makes Silicon dioxide widely used in optical devices.

Excellent insulating properties: 
Silicon dioxide is a superior electrical insulator and is widely used in electronic components.

Stable refractive index: 
With a refractive index of about 1.6, silicon oxide has stable optical properties, making Silicon dioxide suitable for optical glass and optical fibers.

STRUCTURAL CHARACTERISTICS of SILICON DIOXIDE:
Silicon dioxide can exist in several physical forms, including crystalline, amorphous, and nanoparticle states.
The most typical crystalline form is quartz, while amorphous silicon oxide includes materials such as glass and ceramics.

Crystalline structure: 
In quartz, silicon and oxygen atoms alternate to form a three-dimensional network.
Each silicon atom is surrounded by four oxygen atoms, and each oxygen atom is shared by two silicon atoms.
This structure gives quartz its exceptional stability and hardness.

SILICON DIOXIDE STRUCTURE:
Amorphous structure: Amorphous silicon dioxide consists of randomly arranged silicon and oxygen atoms, so it lacks a well-defined crystal structure.
As a result, Silicon dioxide generally has lower density and melting point, making it easier to process at high temperatures.

IS SILICON DIOXIDE SOLUBLE IN WATER?
Silicon dioxide may appear mild, but it has a “dual personality.”
Silicon dioxide is insoluble in water and most acids, yet it can be dissolved by hydrofluoric acid.
Silicon dioxide resists high temperatures but yields to strong alkalis.

These unique chemical properties make Silicon dioxide a highly versatile industrial material.
At high temperatures, silicon dioxide reacts with alkali metal oxides to form silicates, a reaction widely used in glass and ceramic manufacturing.
Interestingly, while concentrated sulfuric and nitric acids have little effect on it, hot concentrated phosphoric acid can corrode silicon dioxide.
Even more surprising, molten borates can dissolve silicon dioxide—an effect cleverly utilized in ceramic firing processes.

WHAT IS SILICON DIOXIDE AND WHAT FOODS CONTAIN IT?
Silicon dioxide, or silica, is a natural chemical compound composed of silicon and oxygen (SiO₂).
Silicon dioxide is typically safe as a food additive, although some agencies are calling for stricter guidelines regarding its use.
Silicon dioxide exists in many forms with the same chemical composition but can have different names, depending on the arrangement of its particles.

Silicon dioxide is most commonly found in the form of quartz, but it also has many uses in industrial and food manufacturing.
One such common use of Silicon dioxide is as an anti-caking agent in food production.
For this purpose, manufacturers use a synthetic amorphous form rather than Silicon dioxide's naturally occurring form.

WHERE DOES SILICON DIOXIDE COME FROM?
Silicon dioxide is most commonly found in nature as quartz, which comprises more than 10% by mass of the earth’s crust.
Silicon dioxide is also present in many living organisms, such as plants and animals.
Silicon dioxide is present in both water and the soil.

In many parts of the world, Silicon dioxide is the major ingredient of sand.
Silicon dioxide is mostly obtained through mining.
Examples are sand mining and purification of quartz.

In Silicon dioxide's natural form, quartz can already be used for many applications.
While this is suitable for some applications, often further chemical processing is required.
This helps to obtain higher purification or certain required qualities.

WHY IS SILICON DIOXIDE ADDED TO FOODS AND PRODUCTS?
Silicon dioxide works as an anti-caking agent, and manufacturers add small amounts to some foods, cosmetics, and more to prevent products from clumping and binding together.

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.

CRYSTALLINE VS AMORPHOUS SILICON DIOXIDE
Silicon dioxide comes in two broad structural families.
In crystalline Silicon dioxide, the tetrahedra are arranged in a regular, repeating, periodic pattern — long-range order.
The common crystalline polymorphs are quartz (stable at room temperature), which on heating inverts from its α to its β form near 573°C and then, at higher temperatures, passes through the tridymite (around 870°C) and cristobalite (around 1470°C) fields before the solid melts near 1713°C.

Quartz is hard (about 7 on the Mohs scale) and is the silica you find in sand and rock crystal.
In amorphous Silicon dioxide, the very same SiO₄ tetrahedra are connected in a random, irregular network with no long-range order — what is known as a continuous random network.
Glass (fused silica), silica gel, fumed (pyrogenic) silica, precipitated silica and colloidal (nano) silica are all amorphous.
The simulator below lets you switch between the two: notice that the local unit is identical in both, and only the long-range arrangement changes.

STRUCTURE of SILICON DIOXIDE:
In the majority of Silicon dioxides, 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 are a manifestation of the double bond rule.
Based on the crystal structural differences, Silicon dioxide can be divided into two categories: crystalline and non-crystalline (amorphous).

In crystalline form, Silicon dioxide can be found naturally occurring as quartz, tridymite (high-temperature form), cristobalite (high-temperature form), stishovite (high-pressure form), and coesite (high-pressure form).
On the other hand, Silicon dioxide can be found in nature as opal and diatomaceous earth.

Quartz glass is a form of intermediate state between these structures.
All of these distinct crystalline forms 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 of SILICON DIOXIDE:
Alpha quartz is the most 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.

Faujasite silica, another polymorph, is obtained by the 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 specific 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 SILICON DIOXIDE:
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.
Its density decreases from 2.08 g/cm3 at 1950 °C to 2.03 g/cm3 at 2200 °C.

MOLECULAR SILICON DIOXIDE:
The molecular SiO2 has a linear structure like CO2.
Silicon dioxide has been produced by combining silicon monoxide (SiO) with oxygen in an argon matrix.

The dimeric Silicon dioxide, (SiO2)2 has been obtained 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.

WHERE IS SILICON DIOXIDE FOUND NATURALLY?
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, Silicon dioxide’s created in labs and used as a common food additive, found in things like baking ingredients, protein powders and dried spices.
Silicon dioxide has a variety of uses in industries ranging from food and cosmetics to construction and electronics.

CHEMICAL REACTIONS of SILICON DIOXIDE:
Silicon dioxide is a relatively inert material (hence its widespread occurrence as a mineral).
Silicon dioxide is often used as inert containers for chemical reactions.
At high temperatures, Silicon dioxide is converted to silicon by reduction with carbon.

Fluorine reacts with Silicon dioxide to form SiF4 and O2 whereas the other halogen gases (Cl2, Br2, I2) are unreactive.
Most forms of Silicon dioxide are attacked ("etched") by hydrofluoric acid (HF) to produce hexafluorosilicic acid:
SiO2 + 6 HF → H2SiF6 + 2 H2O
Stishovite does not react to HF to any significant degree.

HF is used to remove or pattern Silicon dioxide in the semiconductor industry.
Silicon dioxide acts as a Lux–Flood acid, being able to react with bases under certain conditions.
As Silicon dioxide does not contain any hydrogen, non-hydrated silica cannot directly act as a Brønsted–Lowry acid.

While Silicon dioxide is only poorly soluble in water at low or neutral pH (typically, 2 × 10−4 M for quartz up to 10−3 M for cryptocrystalline chalcedony), strong bases react with glass and easily dissolve it.
Therefore, strong bases have to be stored in plastic bottles to avoid jamming the bottle cap, to preserve the integrity of the recipient, and to avoid undesirable contamination by silicate anions.

Silicon dioxide dissolves in hot concentrated alkali or fused hydroxide, as described in this idealized equation:
SiO2+2NaOH⟶Na2SiO3+H2O
Silicon dioxide will neutralise basic metal oxides (e.g. sodium oxide, potassium oxide, lead(II) oxide, zinc oxide, or mixtures of oxides, forming silicates and glasses as the Si-O-Si bonds in silica are broken successively).

As an example the reaction of sodium oxide and Silicon dioxide can produce sodium orthosilicate, sodium silicate, and glasses, dependent on the proportions of reactants:
2Na2O+SiO2⟶Na4SiO4
Na2O+SiO2⟶Na2SiO3
(0.25−0.8)
Na2O+SiO2⟶glass

Examples of such glasses have commercial significance, e.g. soda–lime glass, borosilicate glass, lead glass.
In these glasses, Silicon dioxide is termed the network former or lattice former.
The reaction is also used in blast furnaces to remove sand impurities in the ore by neutralisation with calcium oxide, forming calcium silicate slag.

Silicon dioxide reacts in heated reflux under dinitrogen with ethylene glycol and an alkali metal base to produce highly reactive, pentacoordinate silicates which provide access to a wide variety of new silicon compounds.

The silicates are essentially insoluble in all polar solvent except methanol.
Silicon dioxide reacts with elemental silicon at high temperatures to produce SiO:
SiO2+Si⟶2SiO

WATER SOLUBILITY of SILICON DIOXIDE:
The solubility of Silicon dioxide in water strongly depends on its crystalline form and is three to four times higher for Silicon dioxide than quartz; as a function of temperature, it peaks around 340 °C (644 °F).

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 for 1–2 months.

These crystals are a source of very pure quartz for use in electronic applications.
Above the critical temperature of water 647.096 K (373.946 °C; 705.103 °F) and a pressure of 22.064 megapascals (3,200.1 psi) or higher, water is a supercritical fluid and solubility is once again higher than at lower temperatures.

NATURAL OCCURRENCE of SILICON DIOXIDE:
GEOLOGY
Silicon dioxide is most commonly encountered 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.

BIOLOGY of SILICON DIOXIDE:
Even though Silicon dioxide is poorly soluble, silica occurs in many plants such as rice.
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 insects 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 as supplementary cementitious material (SCM) in cement and concrete manufacturing.

Silicification in and by cells has been common in the biological world and it occurs in bacteria, protists, 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, many grasses, and a wide range of dicotyledons.
The spicules forming the skeleton of many sponges.

PURIFICATION METHODS of SILICON DIOXIDE:
Purification of Silicon dioxide for high technology applications uses isopiestic vapour distillation from concentrated volatile acids and is absorbed in high purity water.
The impurities remain behind.
Preliminary cleaning to remove surface contaminants uses dip etching in HF or a mixture of HCl, H2O2 and deionised water.

DERIVATIVES of SILICON DIOXIDE:
Precipitated Silicon dioxide is obtained like silica gel by acidifying an aqueous solution of sodium silicate.
Precipitated Silicon dioxide is used as filler in rubber for automobile tires and reinforcement particulate in elastomers, and as a flatting agent in paints and coatings for improving the flatness of coatings.

INCOMPATIBILITIES of SILICON DIOXIDE:
Silicon dioxide, amorphous is a noncombustible solid.
Generally unreactive chemically.
Silicon dioxide is incompatible with fluorine, oxygen difluoride, chlorine trifluoride.
Silicon dioxide is soluble in molten alkalis and reacts with most metallic oxides at high temperature.

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 is used to prevent the various powdered ingredients from sticking together.

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 FOODS CONTAIN SILICA DIOXIDE:
Silicon dioxide also exists in numerous grains, fruits, and vegetables 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
Silicon dioxide also occurs naturally in the human body, though it is still unclear what the exact role it plays.

WHY IS SILICON DIOXIDE USED IN FOOD ADDITIVES?
Manufacturers use silica to produce a wide range of products, including glass and cement, and it also has applications 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 prevent powdered ingredients from sticking together, allowing them to flow smoothly.

WHERE DO WE FIND SILICON DIOXIDE?
We find silicon dioxide naturally in many foods and beverages.
For example
Bananas
Eggs
Fish
Grains
Green beans
Leafy greens
Milk
Water

We find silicon dioxide added to foods and products.
For example
Salt
Spices
Sugar
Cosmetics (e.g., powders)

KEY PROPERTIES OF SILICON DIOXIDE:
Beyond being chemically inert and thermally stable, silicon dioxide has a few properties worth knowing because they explain its everyday uses:

Hydrophilic surface.
The surface of silica is covered in silanol (Si–OH) groups, and at normal hydroxyl coverage these groups make the surface hydrophilic — they hydrogen-bond water molecules and act as adsorption sites.
This is precisely why silica gel pulls moisture out of the air and why amorphous silica works as a desiccant and anti-caking agent.
(Fumed silica can be deliberately surface-treated to cap those silanols and make it water-repellent for specialty uses, but that is an engineered modification, not the natural state.)

Low solubility.
Silica is essentially insoluble in water under ordinary conditions and dissolves appreciably only under hydrothermal conditions of high temperature and pressure.

Electrical and thermal insulator.
Thermally grown SiO₂ is an excellent electrical insulator, which is the basis of its role in microelectronics, and its low thermal conductivity makes it useful for thermal insulation.

Optical transparency and hardness.
Fused silica is transparent across a wide range of wavelengths (used in optics and optical fiber), and crystalline quartz is hard enough to scratch ordinary glass.

SILICON DIOXIDE IN FOOD: WHY IT IS ADDED
The silica added to food is synthetic amorphous silica, listed on labels as the additive E551.
Its main job is to be an anti-caking agent: it keeps dry, powdered foods free-flowing so they do not clump into a solid mass.
When humidity rises, water condenses at the contact points between powder grains and forms tiny liquid bridges that pull the grains together — the powder cakes.
Fine silica particles coat the grains, keep them apart, and adsorb moisture onto their large hydrophilic surface, so those bridges barely form and the powder keeps pouring.
The simulator below demonstrates this using the angle of repose — the steepness of a poured heap, which is a standard measure of how well a powder flows.

CHEMICAL PROPERTIES of SILICON DIOXIDE:
Silicon dioxide consists of silicon atoms tetrahedrally bonded to oxygen atoms through strong covalent Si–O–Si linkages, forming an extremely stable three-dimensional network.
Silicon dioxide is chemically inert toward most acids, bases, solvents, oxidizing agents, and reducing agents under normal environmental conditions.

Silicon dioxide exhibits remarkable resistance to oxidation, thermal decomposition, and ultraviolet radiation, allowing long-term stability in demanding industrial environments.
Silicon dioxide reacts readily with hydrofluoric acid to form fluorosilicates, making hydrofluoric acid one of the few chemicals capable of dissolving silica.

Synthetic amorphous silica possesses a highly developed internal pore structure and large specific surface area, making Silicon dioxide an excellent adsorbent, carrier, rheology modifier, and reinforcing filler.
Silicon dioxide's surface contains silanol (Si–OH) functional groups that contribute to hydrogen bonding, moisture adsorption, and interactions with polymers, resins, and various organic compounds.

CHARACTERISTICS of SILICON DIOXIDE:
Silicon dioxide exhibits exceptional chemical inertness.
Silicon Dioxide demonstrates outstanding thermal stability at elevated temperatures.
Silicon Dioxide possesses excellent mechanical hardness and abrasion resistance.

Silicon Dioxide provides superior electrical insulation properties.
Silicon dioxide exhibits high optical transparency over a broad wavelength range.
Silicon dioxide maintains excellent weatherability under prolonged environmental exposure.

Silicon dioxide's highly stable crystal structure contributes to outstanding dimensional stability.
Synthetic grades possess high surface area and excellent adsorption capacity.
Silicon dioxide is compatible with numerous organic and inorganic materials.

Silicon dioxide provides excellent reinforcement in elastomers, polymers, and composite materials.
Silicon dioxide exhibits low thermal expansion and excellent resistance to thermal shock.
Silicon dioxide demonstrates long-term stability under harsh chemical and environmental conditions.

PRODUCTION of SILICON DIOXIDE:
Silicon dioxide is mostly obtained by mining, including sand mining and purification of quartz.
Quartz is suitable for many purposes, while chemical processing is required to make a purer or otherwise more suitable (e.g. more reactive or fine-grained) product.

***Precipitated silica
Precipitated silica or Silicon dioxide is produced by the acidification of solutions of sodium silicate.
The gelatinous precipitate or silica gel, is first washed and then dehydrated to produce colorless microporous silica.
The idealized equation involving a trisilicate and sulfuric acid is:

Na2Si3O7+H2SO4⟶3SiO2+Na2SO4+H2O
Approximately one billion kilograms/year (1999) of silica were produced in this manner, mainly for use for polymer composites – tires and shoe soles.

***On microchips
Thin films of silica grow spontaneously on silicon wafers via thermal oxidation, producing a very shallow layer of about 1 nm or 10 Å of so-called native oxide.
Higher temperatures and alternative environments are used to grow well-controlled layers of Silicon dioxide on silicon, for example at temperatures between 600 and 1200 °C, using so-called dry oxidation with O2

Si+O2⟶SiO2
or wet oxidation with H2O.

Si+2H2O⟶SiO2+2H2
The native oxide layer is beneficial in microelectronics, where it acts as electric insulator with high chemical stability.
It can protect the silicon, store charge, block current, and even act as a controlled pathway to limit current flow.

COSMETICS INGREDIENTS FUNCTIONS of SILICON DIOXIDE:
*BULKING
*ABSORBENT
*OPACIFYING
*ABRASIVE
*VISCOSITY CONTROLLING
*ANTICAKING

HEALTH BENEFITS AND USES OF SILICON DIOXIDE:
Silicon dioxide, commonly known as silicon or silica, is naturally found in foods and mineral water.
Silicon dioxide's also used as an additive in certain foods (with the code E551).
More research is needed to understand its benefits and safety.

**May Support Bone Health
Silicon supplements may strengthen cartilage and bones.
In men with knee osteoarthritis—a bone-related condition that causes joint pain—taking silicon supplements for 12 weeks improved pain, stiffness, and physical function.

**May Improve Skin, Hair, and Nail Health
Early research suggests silicon dioxide may improve skin, hair, and nail health, though larger studies are needed to confirm these claims.
In one study, participants experienced improved hair loss, hair quality, and skin and nail health after five months of taking the supplement.
However, the study size was small, and there was no control group (a group that didn't take the supplement) to compare the results.

Another study showed no difference in skin barrier function and hydration between participants who took the supplement and those who took the placebo.
Participants who took the silicon supplement showed increased skin elasticity.
The European Food Safety Authority (EFSA) noted insufficient evidence to support the effects of silicon dioxide on bone and skin health.

WHERE CAN YOU FIND SILICON DIOXIDE?
Silicon dioxide is found in soil and several foods.
The most common sources of silicon dioxide include:
Grains: Wheat, rice, oats, and barley
Vegetables: Green beans, potatoes, carrots, beetroots, and radishes
Fruits: Bananas and apples
Foods such as eggs, meat, fish, and milk contain smaller amounts of silicon.
You can also find silicon dioxide in bottled springs and mineral water.

WHAT ABOUT SILICON DIOXIDE AS A FOOD ADDITIVE?
Silicon dioxide (E551) is mainly used in food products to prevent ingredients from sticking together (as an anticaking agent) and to reduce foam formation in liquids (as an anti-foaming agent).
Silicon dioxide's approved in the United States as a food additive (anticaking agent and stabilizer) by the Food and Drug Administration (FDA).

You can find silicon dioxide in certain products, such as:
Dried powdered products
Cereals
Beverage whiteners
Semi-hard and hard cheeses
Oil sprays
Chewing gums
Sugar and syrups
Salt and salt substitutes
Seasonings

Silicon dioxide is one of the least bioavailable forms of silicon, which means it is not absorbed or used by the body as effectively as other forms.
Silicon dioxide mostly passes through the gastrointestinal tract.

WHAT ABOUT SILICON DIOXIDE AS A SUPPLEMENT?
Different types of silicon supplements exist, and orthosilicic acid is the most absorbable form.
Orthosilicic acid is stabilized with different compounds (such as a methyl group, choline, or vanillin) and is generally used in dietary supplements.
You may find silicon in the following supplement forms:

Monomethylsilanetriol (organic silicon)
Choline-stabilized orthosilicic acid
Orthosilicic acid-vanillin complex

Silicon dioxide is a common food additive generally considered safe when used within regulated limits.
Silicon dioxide is primarily used to prevent clumping and improve product quality in processed foods.

THERE ARE TWO TYPES OF SILICON DIOXIDE:
Amorphous: 
The most common in food products, amorphous silicon dioxide is used to prevent caking in processed foods.
Some forms of amorphous silicon dioxide are synthetic.

Crystalline: 
This type is the most common found in nature.
The U.S. Food and Drug Administration (FDA) deems amorphous silicon dioxide safe in foods when properly manufactured.
Silicon dioxide's used as an anti-caking agent, beer stabilizer, or supplement adsorbent, with a limit of 2% of a food's weight.

PHYSICAL and CHEMICAL PROPERTIES of SILICON DIOXIDE:
Chemical Formula: SiO₂
Molar Mass: 60.08 g/mol
Appearance: Transparent or white; colorless, odorless solid
Density: 2.648 g/cm³ (α-quartz), 2.196 g/cm³ (amorphous), 2.2 g/cm³
Melting Point: 1,713 °C (3,115 °F; 1,986 K) (amorphous): 4.88 ; 1,610 °C
Boiling Point: 2,950 °C (5,340 °F; 3,220 K); 2,230 °C
Magnetic Susceptibility (χ): −29.6·10⁻⁶ cm³/mol
Thermal Conductivity: 12 W/(m·K) (‖ c-axis), 6.8 W/(m·K) (⊥ c-axis), 
1.4 W/(m·K) (amorphous): 12.213 

Refractive Index (nD): 1.544 (o), 1.553 (e): 4.143 
Physical State: Solid
Color: White
Odor: No data available
Melting Point/Freezing Point: No data available
Initial Boiling Point and Boiling Range: 2,230 °C
Flammability (solid, gas): The product is not flammable.
Upper/Lower Flammability or Explosive Limits: No data available

Flash Point: Not applicable
Autoignition Temperature: No data available
Decomposition Temperature: No data available
pH: No data available
Viscosity:
– Viscosity, kinematic: No data available
– Viscosity, dynamic: No data available

Water Solubility: Insoluble; no data available
Partition Coefficient (n-octanol/water): No data available
Vapor Pressure: No data available
Density: No data available
Relative Density: No data available
Relative Vapor Density: No data available
Particle Characteristics: No data available
Explosive Properties: No data available

Oxidizing Properties: None
Other Safety Information:
– Bulk Density: ca. 200–800 kg/m³
– Particle Size: < 2 mm
CAS Numbers: 14808-60-7, 112945-52-5, 60676-86-0, 7631-86-9, 99439-28-8
EINECS Numbers: 215-683-2, 238-878-4, 262-373-8, 231-545-4
InChI: InChI=1/O2Si/c1-3-2
Molecular Formula: O₂Si
Storage Condition: Room temperature
MDL Number: MFCD00011232
Compound Canonicalized: Yes

Appearance: White powder, granules, beads, or colorless crystalline solid
Color: White or colorless
Odor: Odorless
Physical State: Solid
Chemical Formula: SiO₂
Molecular Weight: 60.08 g/mol
Crystal Structure: Amorphous or crystalline (quartz, cristobalite, tridymite)
Density (Amorphous): Approximately 2.2 g/cm³

Density (Quartz): Approximately 2.65 g/cm³
Melting Point: Approximately 1710°C
Boiling Point: Approximately 2230°C
Mohs Hardness: Approximately 7
Refractive Index: Approximately 1.46
Water Solubility: Insoluble
Solubility in Organic Solvents: Insoluble
Solubility in Hydrofluoric Acid: Soluble (reacts readily)

pH (4% Suspension): Approximately 6.0–8.5
Specific Surface Area: Varies significantly depending on grade (typically 50–800 m²/g for synthetic silica)
Particle Size: Nanometer to several hundred micrometers depending on product grade
Bulk Density: Variable depending on manufacturing process
True Density: Approximately 2.2–2.65 g/cm³
Thermal Conductivity: Low
Electrical Conductivity: Very low (excellent electrical insulator)

Dielectric Constant: Approximately 3.8–4.2
Vapor Pressure: Negligible
Volatility: Non-volatile
Flash Point: Not applicable
Autoignition Temperature: Not applicable
Flammability: Non-flammable
Explosion Hazard: Not explosive
Oxidizing Properties: None
Reducing Properties: None

Hygroscopicity: Low to moderate depending on grade
UV Stability: Excellent
Weather Resistance: Excellent
Thermal Stability: Outstanding
Chemical Stability: Excellent under normal conditions
Corrosion Resistance: Excellent
Mechanical Strength: High
Abrasion Resistance: Excellent
Adsorption Capacity: High (especially porous grades)
Oil Absorption: Moderate to high depending on porosity

Chemical Name: Silicon Dioxide
Common Name: Silica
IUPAC Name: Silicon Dioxide
Chemical Type: Inorganic Oxide
Chemical Family: Silicon Oxide
CAS No.: 7631-86-9 (Amorphous Silicon Dioxide)
EC No.: 231-545-4
Molecular Formula: SiO₂
Molecular Weight: 60.08 g/mol
Chemical Classification: Inorganic Compound

Physical State: Solid
Appearance: White Powder, Granules, or Colorless Crystals (depending on form)
Molecular Weight: 60.084 g/mol
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 2
Rotatable Bond Count: 0
Exact Mass: 59.966755773 Da
Monoisotopic Mass: 59.966755773 Da
Topological Polar Surface Area: 34.1 Ų

Heavy Atom Count: 3
Formal Charge: 0
Complexity: 18.3
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Canonicalized: Yes

Molecular Formula: O2Si
Lewis Structure
Molecular Weight: 60.08
MDL Number: MFCD00148343
MOL File: 7631-86-9.mol
Melting Point: >1600 °C(lit.)
Boiling Point: >100 °C(lit.)
Density: 2.2-2.6 g/mL at 25 °C
Bulk Density: 200-800kg/m3
Vapor Pressure: 13.3hPa at 1732℃

Refractive Index: 1.46
Flash Point: 2230°C
Storage Temp.: 2-8°C
Solubility: Practically insoluble in water and in mineral acids except hydrofluoric acid. 
It dissolves in hot solutions of alkali hydroxides.
Form: suspension
pKa: 6.65-9.8[at 20 ℃]
Specific Gravity: 2.2
Color: White to yellow
PH: 5-8 (100g/l, H2O, 20℃)(slurry)

Odor: at 100.00%. odorless
Resistivity: 1∞10*20 (ρ/μΩ.cm)
Water Solubility: insoluble
Sensitive: Hygroscopic
Hydrolytic Sensitivity: 6: forms irreversible hydrate
Crystal Structure: Trigonal
Merck: 14,8493
Exposure Limits: NIOSH: IDLH 3000 mg/m3; TWA 6 mg/m3
Stability: Stable.
InChI: 1S/O2Si/c1-3-2
InChIKey: VYPSYNLAJGMNEJ-UHFFFAOYSA-N
SMILES: Si=O
CAS DataBase Reference: 7631-86-9(CAS DataBase Reference)

Substances Added to Food (formerly EAFUS): SILICON DIOXIDE
FDA 21 CFR: 173.340; 175.105; 175.300;175.320; 176.170; 176.180;176.200; 176.210; 177.1200;177.2250; 177.2420; 177.2600
FDA UNII: ETJ7Z6XBU4
NIST Chemistry Reference: Silicon(iv) oxide(7631-86-9)
IARC: 3 (Vol. Sup 7, 68) 1997
EPA Substance Registry System: Silica (7631-86-9)
ECETOC JACC REPORT: Silicon dioxide (7631-86-9)
Cosmetics Info: Silica
Toxicological Profile|ATSDR: Silicon dioxide|Toxicological Profile|ATSDR
UNSPSC Code: 41123003
NACRES: NA.24

FIRST AID MEASURES of SILICON DIOXIDE:
-Description of first-aid measures
*General advice:
Show this material safety data sheet to the doctor in attendance.
*If inhaled:
After inhalation: 
Fresh air.
*In case of skin contact: 
Take off immediately all contaminated clothing. 
Rinse skin with
water/ shower.
*In case of eye contact:
After eye contact: 
Rinse out with plenty of water. 
Call in ophthalmologist. 
Remove contact lenses.
*If swallowed:
After swallowing: 
Immediately make victim drink water (two glasses at most). 
Consult a physician.
-Indication of any immediate medical attention and special treatment needed.
No data available

ACCIDENTAL RELEASE MEASURES of SILICON DIOXIDE:
-Environmental precautions:
Do not let product enter drains.
-Methods and materials for containment and cleaning up:
Cover drains. 
Collect, bind, and pump off spills. 
Observe possible material restrictions. 
Take up dry. 
Dispose of properly. 
Clean up affected area.

FIRE FIGHTING MEASURES of SILICON DIOXIDE:
-Extinguishing media:
*Suitable extinguishing media:
Carbon dioxide (CO2) 
Foam 
Dry powder
*Unsuitable extinguishing media:
For this substance/mixture no limitations of extinguishing agents are given.
-Further information:
Prevent fire extinguishing water from contaminating surface water or the ground water system.

EXPOSURE CONTROLS/PERSONAL PROTECTION of SILICON DIOXIDE:
-Control parameters:
--Ingredients with workplace control parameters:
-Exposure controls:
--Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection. 
Safety glasses
*Body Protection:
protective clothing
*Respiratory protection:
Recommended Filter type: Filter A 
-Control of environmental exposure:
Do not let product enter drains.

 
HANDLING and STORAGE of SILICON DIOXIDE:
-Conditions for safe storage, including any incompatibilities:
*Storage conditions:
Tightly closed. 
Dry.

STABILITY and REACTIVITY of SILICON DIOXIDE:
-Chemical stability:
The product is chemically stable under standard ambient conditions (room temperature).
-Possibility of hazardous reactions:
No data available