Hexafluorosilicic acid is the chemical compound with the formula H2SiF6. The free acid is encountered as an equilibrium mixture with hexaflurorosilicate anion (SiF62−) only in solution in solvents that are proton donors at low pH. In aqueous solution, evaporation of H2SiF6 results in loss of HF and SiF4. H2SiF6 is a by-product from the reaction of fluoroapatite with sulfuric acid, which produces HF, which in turn reacts with silicate minerals: SiO2 + 6 HF → H2SiF6 + 2 H2O
Hexafluorosilicic acid is the chemical compound with the formula H2SiF6. The free acid is encountered as an equilibrium mixture with hexaflurorosilicate anion (SiF62−) only in solution in solvents that are proton donors at low pH. In aqueous solution, evaporation of H2SiF6 results in loss of HF and SiF4. H2SiF6 is a by-product from the reaction of fluoroapatite with sulfuric acid, which produces HF, which in turn reacts with silicate minerals: SiO2 + 6 HF → H2SiF6 + 2 H2O Aqueous solutions of H2SiF6 contain the hexafluorosilicate anion, SiF62−. In this octahedral anion, the Si-F bond distances are 1.71 Å.