Molecular formula: Na2SO4 Molecular weight: 142.04 Property: white granular crystal or powder , Na2SO4· 7H2O) is white rhombic crystal . Uses: used as filler of detergent, the making of sodium sulphide, water glass, or used in papermaking, glass, dye and used as filler, dyeing auxiliary, laxative, antidote, t also can be used in fiber, lether, metallurgy, enamel and soap.