Sodium triphosphate, also sodium tripolyphosphate, or tripolyphosphate, is an inorganic compound with formula Na P O. It is the sodium salt of the polyphosphate penta-anion, which is the conjugate base of triphosphoric acid. Wikipedia Formula: Na5P3O10 Molar mass: 367.864 g/mol Density: 2.52 g/cm³ Melting point: 622° Appearance: white powder