Antimony trioxide CasNo.: 1309-64-4 is commonly known as antimony white, in the form of white powder ,is an amphoteric oxide , insoluble in water, ethanol , dilute sulfuric acid and dilute nitric acid, but soluble in concertrated hydrochloric acid , sulfuric acid, strong alkali and tartaric acid solution , the Molecular formula is Sb2O3, the molecular weight is 291.5 , the density is 5.3g/cm3,  the melting point is 656 cet degree. And the boiling point is 1570 cet degree