Ca5(PO4)3(OH) is a chemical compound known as hydroxyapatite. It is a naturally occurring mineral form of calcium phosphate and is primarily found in human and animal bones and teeth. Hydroxyapatite plays a crucial role in providing structural support and strength to these biological tissues. This compound has a chemical formula that indicates it contains five calcium ions, three phosphate groups, and one hydroxide ion. Hydroxyapatite is also used in various medical and dental applications, including bone grafts and dental implants, due to its biocompatibility and ability to promote bone regeneration.