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Hexafluorosilicic acid

CAS Number
16961-83-4
EC Number
N/A
Chemical Formula
F6Si.2H
Molecular Weight
144.091 g/mol

Description

Hexafluorosilicic acid (CAS 16961-83-4 ), also known as fluorosilicic acid, is a strong inorganic acid supplied primarily as an aqueous solution. It is produced as a byproduct of phosphate fertilizer manufacturing. This chemical serves as a cost-effective source of fluoride and silicon across several industrial sectors. In municipal water treatment, it is the most commonly used chemical for drinking water fluoridation. The acid is dosed to regulated concentration targets to ensure safety and efficacy. The construction and concrete industry uses it to harden and densify cementitious surfaces by reacting with calcium compounds. This reaction forms insoluble silicates that reduce porosity and improve wear resistance. In metal surface treatment, it functions as an etchant and adhesion promoter for preparing various substrates. It is frequently used prior to coating or plating operations to ensure quality. Mining operations use it in ore processing and as a pH-regulating agent in leaching circuits for mineral extraction. Fluorosilicic acid is supplied as an aqueous solution, with 20–25% and 23% w/w concentrations being the most commercially standard. These concentrations are ideal for water treatment applications. Higher-concentration solutions up to approximately 35% are available for industrial uses. Technical grade is the predominant market specification for most large-scale manufacturing and processing needs. Product quality is typically referenced against water treatment authority standards or regional regulatory requirements. This ensures the material meets the necessary safety profiles for public infrastructure. Contact us for supply of Hexafluorosilicic acid Request Quote

Other Names (Synonyms)

Hexafluorosilicon(2-);hydron | Fluorosilicic acid

Key Technical Features

  • High Purity Grade standard
  • Consistent Batch Quality
  • Full Regulatory & REACH Support
  • Global Logistics Network enabled

Physical Properties

Boiling Point115.4 °C
Density1.22 g/mL at 25 °C
Flash Point108-109°C
Appearancecolourless liquid
often supplied as a colourless solution in water
ColorClear colorless
FormLiquid
Water SolubilityMiscible with water.
Vapor Pressure23hPa at 19.85℃
Refractive Index1.3500

Safety & Handling

Danger
GHS05· CorrosiveGHS06· ToxicGHS07· IrritantGHS08· Health Hazard

Hazard Statements

H290May be corrosive to metals
H302Harmful if swallowed
H311Toxic in contact with skin
H314Causes severe skin burns and eye damage
H318Causes serious eye damage
H332Harmful if inhaled
H335May cause respiratory irritation
H371May cause damage to organs
H372Causes damage to organs through prolonged or repeated exposure
H373May causes damage to organs through prolonged or repeated exposure
H402Harmful to aquatic life
H412Harmful to aquatic life with long lasting effects

Precautionary Statements

P234Keep only in original packaging.
P260Do not breathe dust/fume/gas/mist/vapours/spray.
P261Avoid breathing dust/fume/gas/mist/vapours/spray.
P262Do not get in eyes, on skin, or on clothing.
P264Wash … thoroughly after handling.
P270Do not eat, drink or smoke when using this product.
P271Use only outdoors or in a well-ventilated area.
P273Avoid release to the environment.
P280Wear protective gloves/protective clothing/eye protection/face protection.
P316Get emergency medical help immediately.
P317Get emergency medical help.
P319Get medical advice/attention if you feel unwell.
P321Specific treatment (see … on this label).
P330Rinse mouth.
P363Wash contaminated clothing before reuse.
P390Absorb spillage to prevent material damage.
P405Store locked up.
P406Store in a corrosion-resistant/… container with a resistant inner liner.
P501Dispose of contents/container in accordance with local regulations.
P265Wash … thoroughly after handling.
P317Get emergency medical help.
P352IF ON SKIN: Wash with plenty of water.
P340IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P316Get emergency medical help immediately.
P364Take off immediately all contaminated clothing and wash it before reuse.
P233Store in a well-ventilated place. Keep container tightly closed.
P331Rinse mouth. Do NOT induce vomiting.
P354IF ON SKIN: Take off immediately all contaminated clothing. Rinse skin with water/shower.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code28111990
UN Number1778
ADR Class8
Packing GroupII
Storage Class6.1D - Non-combustible acute toxic Cat.3 toxic hazardous materials or hazardous materials causing chronic effects
WGK (Germany)3