What is it? Mn2O3 Pulver ? Manganese oxide trioxide, a compound with the chemical formula Mn2O3, and a molecularweight of 157.88, is an oxide. Black cubic crystals. Relative densities 4.50 Water, acetic acid, and ammonium chloride solution are insoluble. It is also insoluble in other inorganic acid. Cold hydrochloric acid is used to dissolve the…