Calcium borate

Calcium borate

Calcium borate
CAS number  N
ChemSpider  YesY
Jmol-3D images Image 1
Image 2
Molecular formula Ca3(BO3)2
Molar mass 237.852 g/mol
Appearance bluish white crystal
Flash point Non-flammable
LD50 590 mg/kg (oral, mouse)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N   YesY/N?)

Calcium borate (Ca3(BO3)2), also called Gerstley borate, is a bluish white crystal with a very defined structure. It can be prepared by reacting calcium metal with boric acid. The resulting precipitate is calcium borate. A hydrated form occurs naturally as the minerals colemanite, nobleite and priceite.

One of its uses is as a binder in some grades of hexagonal boron nitride for hot pressing. Other uses are e.g. flame retardant in epoxy molding compounds, a ceramic flux in some ceramic glazes, reactive self-sealing binders in hazardous waste management,[1] additive for insect-resistant polystyrene,[2] fertilizer, and production of boron glasses.


  1. ^ Calcium Borate Binders. (PDF) . Retrieved on 2010-02-08.
  2. ^ Calcium borate infused foam building materials and the like and method of making same - US Patent 6667350 Claims. Retrieved on 2010-02-08.