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 nutritional value[2] and are found in many living organisms, e.g., bone mineral and tooth enamel.[3] 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).[4] 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).

For the function of calcium phosphate in organisms, see Calcium metabolism.
Calcium phosphate

Calcium Phosphate nanowires seen in SEM
Identifiers
EC Number
  • 233-283-6
E number E341 (antioxidants, ...)
UNII
  • Key: QORWJWZARLRLPR-UHFFFAOYSA-H
Properties
Ca3(PO4)2
Molar mass 310.18 g/mol
Appearance White Solid
Odor Odorless
Density 3.14 g/cu cm[1]
Melting point 1,670 °C (3,040 °F; 1,940 K)[1]
Practically insoluble with water
Solubility in Ethanol Insoluble with ethanol (also acetic acid)
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H315, H319, H335
P101, P102, P103, P261, P264, P270, P271, P280, P302+P352, P304+P340, P305+P351+P338
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
2
0
1
Flash point Non-flammable
Safety data sheet (SDS) fishersci.com
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Orthophosphates, di- and monohydrogen phosphates

These materials contain Ca2+ combined with PO3−
4, HPO2−
4, or H
2PO−
4:

  • 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
2O4−
7 and triphosphate P
3O5−
10:

Hydroxy- and oxo-phosphates

These materials contain other anions in addition to phosphate:

Urine stones
Urine crystals comparison, with calcium phosphate crystal depicted at top center.

Calcium phosphate stones account for approximately 15% of kidney stone disease. Calcium phosphate stones tend to grow in alkaline urine, especially when Proteus bacteria are present. It is the most common type in pregnant women.[5]

References
  1. "Calcium Phosphate".
  2. 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. S2CID 94458523.
  3. "What Substances Make Up Your Teeth? – Affordable Dental Care". www.towncaredental.com. 2015-07-15. Retrieved 2021-01-29.
  4. A. Y. Tamime, ed. (2006). Brined cheeses - The Society of Dairy Technology (SDT). Wiley-Blackwell. ISBN 978-1-4051-2460-7.
  5. Frassetto L, Kohlstadt I (2011). "Treatment and prevention of kidney stones: an update". Am Fam Physician. 84 (11): 1234–42. PMID 22150656.
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