Bismuth hydroxide is an inorganic compound with the chemical formula Bi (OH)three, soluble in concentrated acid and glycerin, insoluble in water, ethanol and concentrated alkali, decomposes in hot water or at 415 ℃, and loses one molecule of water when heated to 100 ℃.It is a new kind of inorganic bismuth catalyst, which is suitable for cathodic electrophoretic paint system, replacing toxic organotin catalyst to prepare environmental friendly coatings.[2-3]