Sodium triphosphate (STP), also sodium tripolyphosphate (STPP), or tripolyphosphate (TPP) is an inorganic compound with the formula Na5P3O10. It is the sodium salt of the polyphosphate Penta-anion, which is the conjugate base of triphosphoric acid. It is produced on a large scale as a component of many domestic and industrial products, especially detergents. Environmental problems associated with eutrophication are attributed to its widespread use.