Antimony trioxide , also known as antimony ( III ) oxide , is a chemical compound .
Antimony trioxide is an amphoteric oxide , dissolving in alkaline solution to give antimonites and in acid solution to given a range of polyantimonous acids . It can be readily oxidized to antimony pentoxide and related antimony ( V ) compounds , but it is also easily reduced to antimony , sometimes with production of stibine .