Ca5(PO4)3Cl, commonly known as chlorapatite, is a mineral that belongs to the apatite group. It consists of calcium, phosphate, and chloride ions, with a chemical formula indicating that it contains five calcium atoms, three phosphate groups, and one chloride atom. This mineral is often found in sedimentary rocks and is a significant component of bone and teeth in many organisms. Chlorapatite plays a crucial role in the biological processes of calcium and phosphorus metabolism. It is less soluble than other forms of apatite, making it more stable in biological environments. This stability contributes to its importance in the formation and maintenance of hard tissues in animals, including humans.