Hexafluorosilicic acid
CAS 16961-83-4
EC 241-034-8
Formula F6Si.2H
MW 144.09 g/mol
Inorganic Acids Water TreatmentBuilding & ConstructionMining & Metals Cross-linking & CuringpH Regulation & BufferingCoagulation & FlocculationChelation & SequestrationCorrosion Inhibition
Description
Hexafluorosilicic acid (CAS 16961-83-4, EC 241-034-8, H2SiF6) is an inorganic acid supplied as an aqueous solution, commonly referred to as fluosilicic acid, hydrofluorosilicic acid, or fluorosilicic acid. It carries no assigned E-code and is not classified as a food additive.
In water treatment, it serves as the primary fluoridation agent, releasing fluoride ions under controlled pH to achieve target dosing levels in municipal systems. In building and construction, it acts as a concrete hardener and crosslinker, reacting with free calcium hydroxide in cement matrices to form insoluble calcium fluorosilicate, increasing surface density and resistance to wear.
The product is available as an aqueous solution, typically at concentrations between 20% and 35% w/w, and is subject to REACH registration requirements within the EU. Procurement should confirm technical or industrial grade specifications with the supplier, as no Ph.Eur. or FCC monograph applies. HS code 28111990 governs import classification.
In water treatment, it serves as the primary fluoridation agent, releasing fluoride ions under controlled pH to achieve target dosing levels in municipal systems. In building and construction, it acts as a concrete hardener and crosslinker, reacting with free calcium hydroxide in cement matrices to form insoluble calcium fluorosilicate, increasing surface density and resistance to wear.
The product is available as an aqueous solution, typically at concentrations between 20% and 35% w/w, and is subject to REACH registration requirements within the EU. Procurement should confirm technical or industrial grade specifications with the supplier, as no Ph.Eur. or FCC monograph applies. HS code 28111990 governs import classification.
Physical Properties
| Boiling Point | 115.4 °C |
| Density | 1.22 g/mL at 25 °C |
| Flash Point | 108-109°C |
| Appearance | colourless liquid; often supplied as a colourless solution in water |
| Color | Clear colorless |
| Form | Liquid |
| Water Solubility | Miscible with water. |
| Vapor Pressure | 23hPa at 19.85℃ |
| Refractive Index | 1.3500 |
Safety & Handling (Learn More)
Danger GHS05 GHS06 GHS07 GHS08
H
H290H302H311H314H318H332H335H371H372H373H402H412
P
P234P260P261P262P264P270P271P273P280P316P317P319P321P330P363P390P405P406P501P264+P265P301+P317P302+P352P304+P340P308+P316P361+P364P403+P233P301+P330+P331P302+P361+P354P305+P354+P338
Trade & Regulatory
| HS Code | 28111990 |
| UN Number | 1778 |
| ADR Class | 8 |
| Packing Group | II |
| Storage Class | 6.1D - Non-combustible acute toxic Cat.3 toxic hazardous materials or hazardous materials causing chronic effects |
| WGK (Germany) | 3 |
Other Names
ACTHACTH 1-39CORTICOTROPINCORTICOTROPHINCORTICOTROPIN AFluosilicic acidACTH (1-39), HUMANFluorosilicic acidCORTICOTROPIN (HUMAN)
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Derivatives
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