Hydroxyapatites

**Definition:** A group of compounds with the general formula M10(PO4)6(OH)2, where M is barium, strontium, or calcium. The compounds are the principal mineral in phosphorite deposits, biological tissue, human bones, and teeth. They are also used as an anticaking agent and polymer catalysts. (Grant & Hackh's Chemical Dictionary, 5th ed)

**Tree numbers:** - D01.029.260.700.675.374.075.025.300 - D01.146.360.050.300 - D01.578.122.477 - D01.695.625.675.650.075.025.300

**Synonyms:** - Hydroxyapatite Derivatives