Article · Wikipedia archive · Last revised Jun 4, 2026

Calcium borate

Calcium borate is a borate salt of calcium with the molecular formula Ca3(BO3)2. 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.

Last revised
Jun 4, 2026
Read time
≈ 1 min
Length
277 w
Citations
5
Source
Calcium borate
Names
IUPAC names
Calcium borate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.034.131
UNII
  • InChI=1S/2BO3.3Ca/c2*2-1(3)4;;;/q2*-3;3*+2 checkY
    Key: VLCLHFYFMCKBRP-UHFFFAOYSA-N checkY
  • InChI=1/4BO3.6Ca/c4*2-1(3)4;;;;;;/q4*-3;6*+2
    Key: KKKYJLNWARAYSD-UHFFFAOYAA
  • InChI=1/2BO3.3Ca/c2*2-1(3)4;;;/q2*-3;3*+2
    Key: VLCLHFYFMCKBRP-UHFFFAOYAG
  • [Ca+2].[Ca+2].[Ca+2].[O-]B([O-])[O-].[O-]B([O-])[O-]
Properties
Ca3(BO3)2
Molar mass 237.852 g/mol
Appearance bluish white crystal
Hazards
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
590 mg/kg (oral, mouse)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Calcium borate is a borate salt of calcium with the molecular formula Ca3(BO3)2. 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 colemanite1, nobleite2 and priceite3.

Use

Calcium borate is used as a binder in some grades of hexagonal boron nitride for hot pressing.

Other uses include as a flame retardant in epoxy molding compounds, a ceramic flux in some ceramic glazes, reactive self-sealing binders in hazardous waste management,4 additive for insect-resistant polystyrene,5 fertilizer, and in the production of boron glasses.

It is used as a main source of boron oxide in the manufacturing of ceramic frits used in ceramic glaze or ceramic engobe for wall and floor ceramic tiles.

References

References

  1. "Colemanite". www.mindat.org. Retrieved 2025-12-14.
  2. "Nobleite". www.mindat.org. Retrieved 2025-12-14.
  3. "Priceite". www.mindat.org. Retrieved 2025-12-14.
  4. Calcium borate binders. (PDF) . Retrieved on 2010-02-08.
  5. Calcium borate infused foam building materials and the like and method of making same - US Patent 6667350 Claims Archived 2011-06-12 at the Wayback Machine. Patentstorm.us. Retrieved on 2010-02-08.