Silvery white metal, soluble in HCl and tartaric acid, insoluble in water and acetic acid.

Used as flame retardant additives for polypropylene, polystyrene, polyvinyl polystyrene, polyvinyl chloride, nylon, ABS, rubber, paint, coating, synthetic resin and paper.

Used as activator in polyester fiber to remove the hidden air in molten glass. Used as covering agent and whitening agent in enameled and ceramic products. Used as deactivators in the catalytic cracking and catalytic reforming processes of heavy oil and residual oil of petroleum.