Calcium phosphate

Calcium phosphate is the name given to a family of minerals containing calcium ions (Ca²⁺) together with orthophosphates (PO₄^3-), metaphosphates or pyrophosphates (P₂O₇^4-) and occasionally hydrogen or hydroxide ions. Seventy percent of bone is made up of hydroxylapatite, a calcium phosphate mineral. Tooth enamel is also largely calcium phosphate.

Uses

For the production of phosphoric acid and fertilizers, for example in the Odda process. 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.

Calcium phosphate is also a raising agent, with E number E341. It is also used in cheese products.

It is also used as a nutritional supplement. There is some debate about the different bioavailabilities of the different calcium salts.

It is used in a variety of dental products for remineralization.

Another practical application of the compound is its use in gene transfection of cells. It is not too well understood, but the calcium phosphate precipitate and DNA form a complex that is thought to help the DNA enter the cell.

Calcium phosphate compounds

• Calcium dihydrogen phosphate, E341(i): Ca(H₂PO₄)₂
• Calcium hydrogen phosphate, E341(ii): CaHPO₄
• Tricalcium phosphate (or tricalcic phosphate), E341(iii): Ca₃(PO₄)₂
• Calcium phosphate Ca₃(PO₄)₂

References