Potassium pyrophosphate/TKPP Molecular formula: K4P2O7 Molecular weight: 330.33 CAS NO.: 7320-34-5 Specification: in accordance with HG/T 3591-1999 Items Test Value Assay % 99.26 P2O5 % 42.70 Fe % 0.00045 Cl % 0.0049 Heavy metals ( as Pb) % 0.00067 Insol. in water % 0.0065 PH value 10.88