Stannoc Acids

Stannoc Acids. Two compounds, in which an oxide of tin acts the part of an acid, are known: (1) stannic, and (2) metastannic acid. The first may be obtained as a gelatinous precipitate by the addition of an acid to one of lts salts - stannates. Of these salts sodium stannate is very largely employed in calico-printing,; it is obtained by boiling caustic soda with dioxide of tin and has the formula Na₂SnO₃3OH₂.