Calcium Stannate, CaO.SnO₂

Calcium Stannate, CaO.SnO₂, may be obtained as small, transparent, square plates by fusing together stannic oxide and calcium chloride with a small quantity of calcium oxide at red heat for several hours, cooling, and washing with water and very dilute hydrochloric acid. It is not attacked by acids and very little by fused sodium carbonate.

A hydrated compound, CaO.SnO₂.5H₂O, is formed by adding potassium stannate to a solution of calcium chloride' and heating to 100° C., when the gelatinous precipitate first separated is converted into small, colourless, transparent crystals, apparently cubical in shape. It is insoluble in water, but dissolves in cold hydrochloric or nitric acid, forming limpid solutions which gelatinise on heating.