Sodium Tripolyphosphate

Sodium triphosphate, also sodium tripolyphosphate, or tripolyphosphate, is an inorganic compound with formula Na₅P₃O₁₀. It is the sodium salt of the polyphosphate penta-anion, which is the conjugate base of triphosphoric acid.


Molar Weight367.86 g/mol
Melting Point622 °C
Density2.52 g/cc
FormsCrystals (large), Powder (dry), White, Pellets

Uses and Applications

Key applications

  • Buffer agent
  • Water treatment
  • Ceramics
  • Oil and Gas
  • Pulp and paper
  • Textile handling
  • Detergent
  • Cosmetic products


  • Cleaning
  • Water Treatment
  • Coatings & Construction
  • Cosmetics
  • Pulp & Paper

Synonyms: Sodium tripolyphosphate, Pentasodium triphosphate, Sodium triphosphate, STPP, Thermphos, Armofos, Polygon, Tripoly, Rhodiaphos LV, Thermphos N, Empiphos stp-D, Thermphos SPR, PENTASODIUM TRIPOLYPHOSPHATE, Triphosphoric acid, pentasodium salt

Chemical Formula: Na5O10P3· nH2O (n = 0 or 6)

CAS Number: 7758-29-4