Calcium Fluosilicate, CaSiF₆

Calcium Fluosilicate, CaSiF₆, is obtained in a vitreous or crystalline form by heating lime in a current of silicon fluoride. It may be obtained as the crystalline dihydrate, CaSiF₆.2H₂O, by dissolving lime or calcium carbonate in hydrofluosilicic acid and evaporating. It is decomposed by water forming calcium fluoride and silicic acid, and by heat forming silicon fluoride. It is easily soluble in 60 per cent, alcohol. The crystals belong to the monoclinic system.