Borax is used in various household laundry and cleaning products and some tooth cleaning formulas. It is also used as a component of glass and pottery glazes in the ceramics industry, as a solvent for metal-oxide slags in metallurgy, as a flux in welding and soldering, and as a fertiliser additive, a mouthwash, and a water softener.


Molar Weight381.38 g/mol (decahydrate)
Melting Point75°C (decahydrate), 742°C (anhydrous)
Boiling Point1575°C (anhydrous, decomposes)
Density1.72 g/cm³ (decahydrate), 1.815 g/cm³ (pentahydrate)
FormsPowder, White, Solid

Uses and Applications

Key applications

  • Buffer agent
  • Disinfectant
  • Welding
  • Food additive
  • Agricultural
  • Pharmaceuticals
  • Personal care


  • Pharma
  • Cleaning
  • Cosmetics
  • Water Treatment
  • Food
  • Agrobusiness

Synonyms: Sodium Borate, Sodium tetraborate, Disodium tetraborate, E285

Chemical Formula: Na2B4O7.xH2O

CAS Number: 1330-43-4 (anhydrous), 1303-96-4 (decahydrate), 12179-04-3 (pentahydrate)