Tricalcium phosphate

Tricalcium phosphate (CAS 7758-87-4; molar mass approx. 310.18 g/mol) is one of several calcium orthophosphates. It exists in two main high-temperature polymorphs, α-TCP and β-TCP, which differ in crystal structure, solubility and resorption behaviour.

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What is tricalcium phosphate used for?

• Food: authorised in the EU as E 341(iii), mainly as an anti-caking and flow agent in powdered foods and as a calcium source for fortification.
• Pharmaceuticals: used as a tablet diluent, flow aid and calcium supplement.
• Biomaterials: β-TCP is widely used as a resorbable bone-graft substitute and in coatings and composites, often together with hydroxyapatite.
• Industry: applications include ceramics, polishing agents and fertiliser-related products.

Which grades and specifications should buyers check?

The commercial product sold as "tribasic calcium phosphate" is often a calcium phosphate of variable composition that approximates hydroxyapatite, rather than stoichiometric Ca3(PO4)2. For this reason the relevant monograph or specification matters. Pharmacopoeial grades are described in USP–NF, EP and BP, and food grades in FCC and EU food-additive specifications. Implant-grade materials for surgical use are covered by ISO and ASTM standards. A CoA typically reports assay (as Ca or Ca3(PO4)2), loss on ignition, fluoride, heavy metals such as Pb, As and Cd, and particle size. Biomedical grades also report phase purity, usually determined by X-ray diffraction.

How is it handled and regulated?

Tricalcium phosphate is generally not classified as hazardous under GHS. However, fine powders can cause dust exposure, so always consult the supplier's SDS. It is registered under REACH and listed on the TSCA inventory. Store it dry, as the material can absorb moisture and cake.

Related concepts

Related substances include hydroxyapatite, dicalcium phosphate (calcium hydrogen phosphate) and monocalcium phosphate, as well as other calcium orthophosphates. Related topics are anti-caking agents, pharmaceutical excipients and bioceramics used in bone regeneration.