Trisodium Pentaborate

Trisodium Pentaborate

Trisodium pentaborate is a chemical compound with the formula Na3B5O8. It is also known by several other names, including sodium borate pentahydrate, sodium biborate, or simply borax. It is a salt that can form as a monohydrate with formula Na3B5O8(OH)2·H2O, which contains the anion dihydroxydopentaborate [B5O8(OH)2]3−. It may also be called simply sodium pentaborate, but this name is more properly reserved for the compound with elemental formula Na2O·5B2O3·nH2O.


Trisodium pentaborate is a white, crystalline solid that is soluble in water and has a wide range of applications in industry and everyday life. However, it can be toxic if ingested or inhaled, and can cause skin and eye irritation.

  • Chemical formula: B5H2Na3O10
  • Molar mass: 285.03 g·mol−1
  • Appearance: Transparent crystal
  • Solubility in water: Soluble
  • Crystal structure: Orthorhombic


Trisodium pentaborate monohydrate crystallizes as thin plates in the orthorhombic crystal system, with symmetry group Pbca and cell parameters a = 880.4 pm, b = 1837.1 pm, c = 1092.4 pm, formulas per cell Z = 8.


Trisodium pentaborate is commonly used as a cleaning agent, particularly for laundry and household cleaning. It can also be used as a pesticide, a flame retardant, and a buffer in chemical reactions. In addition, trisodium pentaborate is used in the production of ceramics, glass, and enamel, as well as in metallurgy and welding.

It is also used in the manufacture of glass and ceramics, as well as in the production of fertilizers and pesticides. In addition, trisodium pentaborate has several medical applications, such as treating skin conditions like psoriasis and eczema, and as an antifungal agent.

Safety Hazards

However, it is important to note that trisodium pentaborate can be toxic if ingested in large quantities, and prolonged exposure to it can cause skin irritation and other health issues. It is therefore important to use proper protective equipment and handle trisodium pentaborate with care. It is important to handle this compound with care and follow proper safety protocols when working with it.