Stannic Fluoride, SnF 4, is obtained in solution by dissolving hydrated stannic oxide in hydrofluoric acid; it forms a characteristic series of salts, the stannofluorides, M 2 SnF 6, isomorphous with the silico-, titano-, germanoand zirconofluorides.
It is a colourless liquid which boils at 210° C. Water decomposes it with the formation of silico-mesoxalic acid, HOOSi Si(OH) 2 SiOOH.
Alloys of magnesium and silicon are prepared by heating fragments of magnesium with magnesium filings and potassium silico-fluoride.
Silico-oxalic acid, (SiO.
The salts of this acid are well known; they are isomorphous with the silico-, stannoand zircono-fluorides.