Specification White or yellowish powder.sweet toxic. Density of 7.1, melting point 820 , about 200 and above began to lose crystal water, refractive index 2.1. Not dissolve in water and organic solvents, can be dissolved in hot ammonium acetate and alkali, as well as nitric acid, hot concentrated hydrochloric acid. Non-flammable and corrosive, easy moisture absorption, in the wet state of decomposition by the sunlight discoloration. This product has a stabilizing effect on PVC, and has excellent heat resistance and electrical insulation, the light-fastness properties or Special suitable for high-temperature processing.