Sodium Tripolyphosphate, an inorganic compound with the chemical formula Na5P3O10, is an amorphous water-soluble linear polyphosphate that is commonly used in food products as a moisture retention agent, quality improver, pH adjuster, and metal chelator.Sodium Tripolyphosphate has two crystalline forms, type I (high temperature type) and type II (low temperature type). The difference lies in the different bond lengths and bond angles of the two. Both have the same chemical properties, but thermal stability and hygroscopicity are higher in type I than in type II.