Trisodium pentaborate is a salt that can form as a monohydrate with formula Na3B5O8(OH)2·H2O, which contains the anion dihydroxydopentaborate [B5O8(OH)2]3−.[1]

Trisodium pentaborate
Identifiers
3D model (JSmol)
  • InChI=1S/B5H4O10.3Na.H2O/c6-2-10-1-11-5(13-2)14-3(7)12-4(8,9)15-5;;;;/h8-9H,1H2;;;;1H2/q-2;;;;
    Key: GCZJYHCEEQCBQM-UHFFFAOYSA-N
  • [Na].[Na].[Na].O1B([O-])O[B+](O)(O)OB12OB([O-])O[B-]O2.O
Properties
B5H2Na3O10
Molar mass 285.03 g·mol−1
Appearance Transparent crystal
Soluble
Structure
Orthorhombic
Related compounds
Related compounds
probertite, heidornite, garrelsite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Its formula may be incorrectly given as Na3B5O8·2H2O, or as 3Na2O5B2O3·4H2O. It may also be called simply sodium pentaborate,[1] but this name is more properly reserved for the compound with elemental formula Na2O·5B2O3·nH2O.

Structure

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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.[1]

References

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  1. ^ a b c Silvio Menchetti and Cesare Sabelli (1977): "The crystal structure of synthetic sodium pentaborate monohydrate". Acta Crystallographica Section B, volume B33, pages 3730-3733. doi:10.1107/S0567740877011959