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Hexafluorosilicic acid

Hexafluorosilicic acid
Hexafluorosilicic acid structure
Chemical Name:
Hexafluorosilicic acid
Molecular Formula:
Formula Weight:
MOL File:

Hexafluorosilicic acid Properties

Boiling point:
1.22 g/mL at 20 °C (lit.) 1.31 g/mL at 25 °C
refractive index 
Flash point:
storage temp. 
H2O: 1 mg/mL, clear, colorless
Clear colorless
Specific Gravity
1.38 (40%)
Water Solubility 
Miscible with water.
Hydrolytic Sensitivity
0: forms stable aqueous solutions
Stable in aqueous solution.
CAS DataBase Reference
16961-83-4(CAS DataBase Reference)
Indirect Additives used in Food Contact Substances
EWG's Food Scores
EPA Substance Registry System
Fluosilicic acid (16961-83-4)
  • Risk and Safety Statements
Signal word  Danger
Hazard statements  H302-H311-H314-H318
Precautionary statements  P260h-P301+P330+P331-P405-P501a-P280-P301+P312+P330-P303+P361+P353-P304+P340+P310-P305+P351+P338
Hazard Codes  C
Risk Statements  34-35-20/21/22
Safety Statements  26-36/37/39-45-27
RIDADR  UN 1778 8/PG 2
WGK Germany  3
RTECS  VV8225000
Hazard Note  Corrosive
HazardClass  8
PackingGroup  II
HS Code  28111990
Toxicity LD50 oral in rat: 430mg/kg

Hexafluorosilicic acid price More Price(8)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich 372757 Fluorosilicic acid solution 20-25 wt. % in H2O 16961-83-4 500g $58.1 2021-03-22 Buy
Sigma-Aldrich 01302 Fluosilicic acid purum, 33.5-35% 16961-83-4 1l $63.5 2021-03-22 Buy
Sigma-Aldrich A0423 Adrenocorticotropic Hormone human ≥97% (HPLC) 16961-83-4 0.1 mg $188 2021-03-22 Buy
Sigma-Aldrich A0423 Adrenocorticotropic Hormone human ≥97% (HPLC) 16961-83-4 0.5 mg $506 2021-03-22 Buy
Alfa Aesar L14829 Hexafluorosilicic acid, 35% w/w aq. soln. 16961-83-4 500g $42.9 2020-06-24 Buy

Hexafluorosilicic acid Chemical Properties,Uses,Production


Hexafluorosilicic acid is a kind of inorganic acid. It is majorly used for the fluoridation of water in United State to minimize the incidence of dental caries and dental fluorosis. For chemical synthesis, it is majorly used for the manufacturing of aluminum fluoride and cryolite as well as many kinds of hexafluorosilicate salts. It can also be used for the production of silicon and silicon dioxide. It can also be used as an electrolyte in the Betts electrolytic process for refining lead. It is also a specialized reagent in organic synthesis for cleaving Si–O bonds of silyl ethers.

Chemical Properties

Fluosilicic acid,H2SiF6, also known as hydrofluorosilicic acid,is a colorless liquid that is soluble in water. It is highly corrosive and toxic,attacking glass and stoneware. Fluosilicic acid is used in water fluoridation, electroplating, and in manufacturing enamels and cement.

Chemical Properties

Fluorosilicic acid is a transparent, colorless fuming liquid.

Physical properties

d 1.220 g cm?3 for a 25% aq solution.


A fluoride source with both protic and Lewis acid properties providing efficient cleavage of silicon–oxygen bonds, e.g. silyl ether deprotection.


A 1-2% solution is used widely for sterilizing equipment in brewing and bottling establishments. Other concentrations are used in the electrolytic refining of lead, in electroplating, for hardening cement, crumbling lime or brick work, for the removal of lime from hides during the tanning process, to remove molds, as preservative for timber.

General Description

A colorless fuming liquid with a penetrating pungent odor. Corrosive to metals and tissue. Both the fumes and very short contact with the liquid can cause severe and painful burns. Used in water fluoridation, in hardening cement and ceramics, as a wood preservative.

Air & Water Reactions

Fumes in air. Soluble in water with release of heat and corrosive fumes.

Reactivity Profile

Hexafluorosilicic acid can react with strong acids (such as sulfuric acid) to release fumes of toxic hydrogen fluoride. Attacks glass and materials containing silica. Reacts exothermically with chemical bases (examples: amines, amides, inorganic hydroxides). Reacts with active metals, including iron and aluminum to dissolve the metal and liberate hydrogen and/or toxic gases. Can initiate polymerization in certain alkenes. Reacts with cyanide salts and compounds to release gaseous hydrogen cyanide. Flammable and/or toxic gases are also often generated by reactions with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides, and weak or strong reducing agents. Additional gas-generating reactions may occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), and carbonates. Can catalyze (increase the rate of) chemical reactions. Decomposes when heated to the boiling point to produce very toxic and corrosive hydrogen fluoride gas.


Extremely corrosive by skin contact and inhalation.

Health Hazard

Inhalation of vapor produces severe corrosive effect on mucous membrane. Ingestion causes severe burns of mouth and stomach. Contact with liquid or vapor causes severe burns of eyes and skin.

Fire Hazard

Special Hazards of Combustion Products: Irritating fumes of hydrogen fluoride may form in fire.

Industrial uses

Hydrofluorosilicic acid (H2SiF6) is a colorless to light brown liquid. It is also manufactured from calcium fluoride or other fluoride-containing products. Hydrofluorosilic acid is a strong depressant for many silicates during flotation of a number of oxidic minerals. It is used for gangue depression during flotation of tin, columbite and tantalite.

Safety Profile

Poison by subcutaneous route. A corrosive irritant to sktn, eyes, and mucous membranes. Will react with water or steam to produce toxic and corrosive fumes. When heated to decomposition it emits toxic fumes of F-. See also FLUORIDES.

Potential Exposure

A solution of fluorosilicic acid is used for sterilization in the brewing and bottling industry, elec trolytic refining of lead; electroplating, hardening cement; removing mold, and others.


UN1778 Fluorosilicic acid, Hazard class: 8; Labels: 8-Corrosive material.


The aqueous solution is a strong acid. Reacts with water or steam to produce toxic and corrosive fumes of hydrogen fluoride. Incompatible, and may react violently with: bases, aliphatic amines; alkanolamines, alkylene oxides; aromatic amines; amides, ammonia, ammonium hydroxide; calcium oxide; epichlorohydrin, iso cyanates, oleum, organic anhydrides; sulfuric acid; strong oxidizers; vinyl acetate; water. Attacks glass, concrete, and ceramics. The anhydrous form dissociates almost instantly into silicon tetrafluoride and hydrogen fluoride.

Waste Disposal

Add slowly to a large amount of soda ash in solution. Discharge to sewer with large volumes of water


Robinson, Tim. "Innovative Processes in Electrometallurgy." Innovative Process Development in Metallurgical Industry. Springer International Publishing, 2016. 385- 392.
Sarawade, Pradip B., et al. "Recovery of high surface area mesoporous silica from waste hexafluorosilicic acid (H 2 SiF 6) of fertilizer industry." Journal of hazardous materials 173.1 (2010): 576-580.
Kauffman, Joel M. "Water fluoridation: a review of recent research and actions." Journal of American Physicians and Surgeons 10.2 (2005): 38.
Krot, V. V., et al. "ChemInform Abstract: Preparation of Amorphous Silicon Dioxide from Hexafluorosilicic Acid." Cheminform 23.48(1992):no-no.
Zorya, L., and V. Krot. "Method of high-purity silica production from hexafluorosilicic acid." Reaction Kinetics & Catalysis Letters 50.1-2(1993):349-354.

Hexafluorosilicic acid Preparation Products And Raw materials

Raw materials

Preparation Products

Hexafluorosilicic acid Suppliers

Global( 227)Suppliers
Supplier Tel Fax Email Country ProdList Advantage
Henan DaKen Chemical CO.,LTD.
+86-371-66670886 China 20918 58
Henan Tianfu Chemical Co.,Ltd.
0371-55170693 CHINA 22607 55
career henan chemical co
+86-371-86658258 CHINA 29954 58
Hubei Jusheng Technology Co.,Ltd.
027-59599243 CHINA 28229 58
Hebei Guanlang Biotechnology Co., Ltd.
+8619930503282 China 5882 58
Hubei xin bonus chemical co. LTD
027-59338440 CHINA 23035 58
Chongqing Chemdad Co., Ltd
+86-13650506873 CHINA 37282 58
13806087780 +86 13806087780 CHINA 17606 58
Hefei TNJ Chemical Industry Co.,Ltd.
0551-65418697 CHINA 37441 58
Wuhan Monad Medicine Tech Co.,LTD
18771942761 02768782018 CHINA 1000 58

View Lastest Price from Hexafluorosilicic acid manufacturers

Image Release date Product Price Min. Order Purity Supply Ability Manufacturer
2021-11-08 Hexafluorosilicic acid
US $10.00 / KG 500g 99% 2000MT/Month Wuhan wingroup Pharmaceutical Co., Ltd
2021-10-13 Hexafluorosilicic acid
US $10.00 / KG 1KG 99% 10 mt Hebei Guanlang Biotechnology Co., Ltd.
2021-08-31 Hexafluorosilicate
US $10.00 / L 5L/Drum 99.99% 200 tons/month Wuhan Monad Medicine Tech Co.,LTD

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