Bismuth(III) oxide, also known as bismite and bismuth trioxide, is a chemical compound. Its chemical formula is Bi2O3. It has bismuth and oxide ions in it. The bismuth is in its +3 oxidation state.
Bismuth (III) oxide is a yellow, monoclinic crystalline powder. It is insoluble in water and hydroxide solutions but dissolves in acids to form bismuth (III) salts. It can be prepared by heating bismuth in air or by heating hydroxides, carbonates or nitrates of bismuth.