[Properties]: White or colorless, crystal free flowing solid, effloresce in air, soluble in water easily, relative density is 1.63, melting point is 34.6 . [Uses]: Used as boiler water softener; treatment of leather and fabrics to increase weight; flame retardant for fabrics, wood and paper in dyeing; culture medium for biochemical treatment; raw material for production of sodium pyrophosphate and other phosphates.