Sodium Tripoly Phosphate(STPP) (CAS No.: 7758-29-4 ) Executive Standard: GB9983-88 Molecular Formula: Na5P3O10 MW: 367.86 . Character: It is white powder; Byname is Pent-sodium Phosphate; Melting point is 622'C;It has salient chelating capacity to ions of Ca, Mg etc; It can soften the hard water to make suspension become into the clear solution; it has weak alkalinity but no corrosiveness. It is a surfactant which has outstanding emulsification for lubricants and fat; It has different bulk density, i.e. low density 0.35-0.5g/cm3, medium density 0.51-0.65g/cm3 and high density 0.66-0.9g/cm3.This product has two kinds of crystalline forms, namely Type I (the type of high temperature) and Type II (the type of low temperature). The chemical characters of the two types are the same, and the difference between them lies in the thermo stability . Specifications Technical Grade. Main content % Min 94.0. Whiteness % Min 90.0 . P2O5 % Min 57.0. Water Insoluble Matter %Max 0.1. Fe % Max 0.01. PH Value of 1% water solution 9.2-10.0. Bulk Density(g/cm3)% Min 0.5-0.7/0.7-0.95. Package: 25kgs woven bag lined with plastic bag, according to the customer's demand ,Stored at draughty dry places.