|Appearance||White amorphous powder|
|Formula weight||310.18 g/mol|
|Melting point||Liquifies under high pressure at 1670 K (1391 °C)|
|Density||3.14 ×103 kg/m3|
|Solubility||0.002 g in 100g water|
|ΔfH0solid||-982.3 kJ/mol (alpha form)|
|-984.9 kJ/mol (beta form)|
|S0solid||57.58 J/(mol·K) (alpha form)|
|56.4 J/(mol·K) (beta form)|
|Ingestion||Causes irritation to the gastrointestinal tract.|
|Inhalation||Causes irritation to the respiratory tract.|
|Skin||May cause skin irritation.|
|Eyes||May cause irritation and damage to the cornea.|
|More info||Hazardous Chemical Database|
Tricalcium phosphate is a compound with formula Ca3(PO4)2. It is also known as calcium orthophosphate, tertiary calcium phosphate, tribasic calcium phosphate, or "bone ash" (calcium phosphate being one of the main combustion products of bone).
It has an alpha and a beta crystal form, the alpha state being formed at high temperatures. As rock, it is found in Whitlockite.
|Dicalcium phosphate||CaHPO4 (also calcium monohydrogen phosphate)|
|Monocalcium phosphate||Ca(H2PO4)2 (also calcium dihydrogen phosphate)|
|Calcium pyrophosphate||Ca2P2O7 (occurs as alpha, beta and gamma phases)|
In minerals, "calcium phosphate" refers to minerals containing calcium ions (Ca2+) together with orthophosphates (PO43-), metaphosphates or pyrophosphates (P2O74-) and occasionally hydrogen or hydroxide ions.
Especially, the common mineral apatite has formula Ca5(PO4)3X, where X is F, Cl, OH, or a mixture; it is hydroxyapatite if the extra ion is mainly hydroxide. Much of the "tricalcium phosphate" on the market is actually powdered hydroxyapatite.
It is found in nature as a rock in Morocco, Israel, Egypt, and Kola (Russia) and in smaller quantities in some other countries. The natural form is not completely pure, and there are some other components like sand and lime which can change the composition. In terms of P2O5, most calcium phosphate rocks have a content of 30% to 40% P2O5 in weight.
Tricalcium phosphate is used in powdered spices as an anti-caking agent.
Calcium phosphate is also a raising agent (food additives) E341. Is a mineral salt found in rocks and bones, it is used in cheese products.
Another practical application of the compound is its use in gene transfection. The calcium ions can make a cell competent (a euphemism for "rip holes in its membrane") to allow exogenous genes to enter the cell by diffusion. A heat shock afterwards then invokes the cell to repair itself. This is a quick and easy method for transfection, albeit a rather inefficient one.