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Silica, fumed

Silica, fumed
Silica, fumed structure
Chemical Name:
Silica, fumed
Molecular Formula:
Formula Weight:
MOL File:

Silica, fumed Properties

Melting point:
2.3 lb/cu.ft at 25 °C (bulk density)(lit.)
refractive index 
n20/D 1.46(lit.)
Practically insoluble in organic solvents, water, and acids, except hydrofluoric acid; soluble in hot solutions of alkali hydroxide. Forms a colloidal dispersion with water. For Aerosil, solubility in water is 150 mg/L at 258℃ (pH 7).
Specific Gravity
Hydrolytic Sensitivity
5: forms reversible hydrate
CAS DataBase Reference
112945-52-5(CAS DataBase Reference)
EWG's Food Scores
NCI Dictionary of Cancer Terms
EPA Substance Registry System
Silica, amorphous, fumed, cryst.-free (112945-52-5)
  • Risk and Safety Statements
Safety Statements  24/25
WGK Germany  2
RTECS  VV7310000
HS Code  28112290

Silica, fumed price More Price(45)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich SX0076 Sand Sea 112945-52-5 500 g $19.52 2021-12-16 Buy
Sigma-Aldrich 274739 Sand 50-70?mesh particle size 112945-52-5 500 g $39.4 2021-12-16 Buy
Sigma-Aldrich SX0075 Sand Standard, washed and dried 112945-52-5 500 g $47.91 2021-12-16 Buy
Sigma-Aldrich 13767 Silica gel orange with moisture indicator free of heavy metals 112945-52-5 500 g $48.7 2021-12-16 Buy
Sigma-Aldrich 274739 Sand 50-70?mesh particle size 112945-52-5 1 kg $49 2021-12-16 Buy

Silica, fumed Chemical Properties,Uses,Production

Chemical Properties

Amorphous silica, the noncrystalline form of SiO2, is a transparent to gray, odorless, amorphous powder

Chemical Properties

Colloidal silicon dioxide is a submicroscopic fumed silica with a particle size of about 15 nm. It is a light, loose, bluish-white-colored, odorless, tasteless, amorphous powder.


Synthetic Amorphous Silica has interesting thickening and thixotropic properties, and an enormous external surface area. It is produced by a vapor phase hydrolysis process using chlorosilanes or substituted silanes such as, silicon tetrachloride in a flame of hydrogen and oxygen. This material is formed and collected in a dry state. This product contains no detectable crystalline silica.

Production Methods

Colloidal silicon dioxide is prepared by the flame hydrolysis of chlorosilanes, such as silicon tetrachloride, at 18008℃ using a hydrogen–oxygen flame. Rapid cooling from the molten state during manufacture causes the product to remain amorphous.

General Description

Fumed silica may be synthesized by high temperature hydrolysis of SiCl4 in O2(N2)/H2 flame. It is amorphous in nature and possesses very high specific area. The micro droplets of amorphous silica fuse into a branch and form a chain like agglomerate.

Pharmaceutical Applications

Colloidal silicon dioxide is widely used in pharmaceuticals, cosmetics, and food products. Its small particle size and large specific surface area give it desirable flow characteristics that are exploited to improve the flow properties of dry powders in a number of processes such as tableting and capsule filling.
Colloidal silicon dioxide is also used to stabilize emulsions and as a thixotropic thickening and suspending agent in gels and semisolid preparations. With other ingredients of similar refractive index, transparent gels may be formed. The degree of viscosity increase depends on the polarity of the liquid (polar liquids generally require a greater concentration of colloidal silicon dioxide than nonpolar liquids). Viscosity is largely independent of temperature. However, changes to the pH of a system may affect the viscosity1.
In aerosols, other than those for inhalation, colloidal silicon dioxide is used to promote particulate suspension, eliminate hard settling, and minimize the clogging of spray nozzles. Colloidal silicon dioxide is also used as a tablet disintegrant and as an adsorbent dispersing agent for liquids in powders. Colloidal silicon dioxide is frequently added to suppository formulations containing lipophilic excipients to increase viscosity, prevent sedimentation during molding, and decrease the release rate. Colloidal silicon dioxide is also used as an adsorbent during the preparation of wax microspheres; as a thickening agent for topical preparations; and has been used to aid the freeze-drying of nanocapsules and nanosphere suspensions.

Safety Profile

Poison by intraperitoneal, intravenous, and intratracheal routes. Moderately toxic by ingestion. An inhalation hazard. Much less toxic than crystalhe forms. Questionable carcinogen with experimental carcinogenic data. Mutation data reported. Does not cause silicosis. See also other silica entries


Colloidal silicon dioxide is widely used in oral and topical pharmaceutical products and is generally regarded as an essentially nontoxic and nonirritant excipient. However, intraperitoneal and subcutaneous injection may produce local tissue reactions and/or granulomas. Colloidal silicon dioxide should therefore not be administered parenterally.
LD50 (rat, IV): 0.015 g/kg
LD50 (rat, oral): 3.16 g/kg

Potential Exposure

Amorphous fumed silica is used as a mineral, natural or synthetic fiber. A potential danger to those involved in the production and handling of fumed silica for paint pigments or catalysts. Diatomaceous earth is used in clarifying liquids, in manufacture of fire brick and heat insulators; used as a filtering agent; as a filler in construction materials; pesticides, paints, and varnishes. A potential danger to those involved in mining of diatomaceous earth or fabrication of products there from.


Colloidal silicon dioxide is hygroscopic but adsorbs large quantities of water without liquefying. When used in aqueous systems at a pH 0–7.5, colloidal silicon dioxide is effective in increasing the viscosity of a system. However, at a pH greater than 7.5 the viscosityincreasing properties of colloidal silicon dioxide are reduced; and at a pH greater than 10.7 this ability is lost entirely since the silicon dioxide dissolves to form silicates. Colloidal silicon dioxide powder should be stored in a well-closed container.

Purification Methods

Purification of silica 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 [Phelan & Powell Analyst 109 1299 1984].


Silica, amorphous is a noncombustible solid. Generally unreactive chemically. Incompatible with fluorine, oxygen difluoride, chlorine trifluoride. Soluble in molten alkalis and reacts with most metallic oxides at high temperature.


Incompatible with diethylstilbestrol preparations.

Waste Disposal

Sanitary landfill.

Regulatory Status

GRAS listed. Included in the FDA Inactive Ingredients Database (oral capsules, suspensions, and tablets; transdermal, rectal, and vaginal preparations). Also approved by the FDA as a food additive and for food contact. Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Nonmedicinal Ingredients.

Silica, fumed Preparation Products And Raw materials

Raw materials

Preparation Products

Silica, fumed Suppliers

Global( 282)Suppliers
Supplier Tel Fax Email Country ProdList Advantage
Hangzhou Bayee Chemical Co., Ltd.
0086-571-85775919 China 105 55
Henan Tianfu Chemical Co.,Ltd.
0371-55170693 China 22607 55
Hefei TNJ Chemical Industry Co.,Ltd.
86-0551-65418697 China 3000 55
hdzhl biotechnology co., ltd
86-13032617415 CHINA 1275 58
Xiamen AmoyChem Co., Ltd
+86 592-605 1114 CHINA 6369 58
Hubei xin bonus chemical co. LTD
027-59338440 CHINA 23035 58
Shandong chuangyingchemical Co., Ltd.
18853181302 CHINA 5917 58
Shanghai Longyu Biotechnology Co., Ltd.
+86 15821988213 China 2514 58
career henan chemical co
15093356674 0371-55982848
0086-371-86658258 CHINA 29864 58
13806087780 +86 13806087780 CHINA 17384 58

View Lastest Price from Silica, fumed manufacturers

Image Release date Product Price Min. Order Purity Supply Ability Manufacturer
2020-11-26 Silicon Oxide
US $5.50 / KG 100KG 99% 100 Hebei Henghe Import and Export Trading Co. LTD
2019-12-23 Silica, fumed
US $1.00 / KG 1KG 99 100kg Career Henan Chemical Co

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