Calcium phosphate

The term calcium phosphate refers to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are white solids of nutritious value[1] and are found in many living organisms, e.g., bone mineral and tooth enamel.[2] In milk, it exists in a colloidal form in micelles bound to casein protein with magnesium, zinc, and citrate–collectively referred to as colloidal calcium phosphate (CCP).[3] Various calcium phosphate minerals are used in the production of phosphoric acid and fertilizers. Overuse of certain forms of calcium phosphate can lead to nutrient-containing surface runoff and subsequent adverse effects upon receiving waters such as algal blooms and eutrophication (over-enrichment with nutrients and minerals).

Calcium Phosphate nanowires seen in SEM

Orthophosphates, di- and monohydrogen phosphates

These materials contain Ca2+ combined with PO3−
, HPO2−
, or H

  • Monocalcium phosphate, E341 (CAS# 7758-23-8 for anhydrous; CAS#10031-30-8 for monohydrate: Ca(H2PO4)2 and Ca(H2PO4)2(H2O)
  • Dicalcium phosphate (dibasic calcium phosphate), E341(ii) (CAS# 7757-93-9): CaHPO4 (mineral: monetite), dihydrate CaHPO4(H2O)2 (mineral: brushite) and monohydrate CaHPO4(H2O)
  • Tricalcium phosphate (tribasic calcium phosphate or tricalcic phosphate, sometimes referred to as calcium phosphate or calcium orthophosphate, whitlockite), E341(iii) (CAS#7758-87-4): Ca3(PO4)2
  • Octacalcium phosphate (CAS# 13767-12-9): Ca8H2(PO4)6·5H2O
  • Amorphous calcium phosphate, a glassy precipitate of variable composition that may be present in biological systems.

Di- and polyphosphates

These materials contain Ca2+ combined with the polyphosphates, such as P
and triphosphate P

Hydroxy- and oxo-phosphates

These materials contain other anions in addition to phosphate:

  • Hydroxyapatite Ca5(PO4)3(OH)
  • Apatite Ca10(PO4)6(OH,F,Cl,Br)2
  • Tetracalcium phosphate (CAS#1306-01-0): Ca4(PO4)2O


  1. Klaus Schrödter; Gerhard Bettermann; Thomas Staffel; Friedrich Wahl; Thomas Klein; Thomas Hofmann (2008). "Phosphoric Acid and Phosphates". Ullmann's Encyclopedia of Industrial Chemistry. Ullmann’s Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_465.pub3. ISBN 978-3527306732.
  2. "What Substances Make Up Your Teeth? – Affordable Dental Care". 2015-07-15. Retrieved 2021-01-29.
  3. A. Y. Tamime, ed. (2006). Brined cheeses - The Society of Dairy Technology (SDT). Wiley-Blackwell. ISBN 978-1-4051-2460-7.
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