Prep. By precipitating a solution of sulphate of zinc with carbonate of soda, washing and drying the precipitate.

Prop. & Comp. A white powder, without odour or taste, insoluble in water, soluble with effervescence, and without residue, in dilute sulphuric acid, the solution giving a white precipitate with hydrosulphuret of ammonia. The solution in nitric acid gives no precipitate with chloride of barium or nitrate of silver; and with carbonate of ammonia, a white precipitate entirely soluble without colour in excess of the reagent. Composition (Zn O, Co2 + HO) + 2 (Zn O, HO), a compound of the carbonate and hydrated oxide of zinc.

Therapeutics. Not much employed as a medicinal agent; it may be used in the same cases as the oxide, both internally and externally; its action is probably identical with that of the oxide of zinc.

Dose. 1 gr. to 10 gr., in pill or powder.