Trisodium pentaborate is a

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

that can form as a

monohydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was underst ...

with formula , which contains the

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

dihydroxydopentaborate . Its formula may be incorrectly given as , or as . It may also be called simply sodium pentaborate, but this name is more properly reserved for the compound with elemental formula .

Structure

Trisodium pentaborate monohydrate crystallizes as thin plates in the

orthorhombic crystal system In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...

, with

symmetry group In group theory, the symmetry group of a geometric object is the group of all transformations under which the object is invariant, endowed with the group operation of composition. Such a transformation is an invertible mapping of the ambient ...

''Pbca'' and cell parameters ''a'' = 880.4 pm, ''b'' = 1837.1 pm, ''c'' = 1092.4 pm, formulas per cell ''Z'' = 8.

References

Silvio Menchetti and Cesare Sabelli (1977): "The crystal structure of synthetic sodium pentaborate monohydrate". ''Acta Crystallographica Section B'', volume B33, pages 3730-3733. sodium compounds borates {{chem-compound-stub