Apatite is a group of phosphate minerals, usually referring to hydroxyapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH?, F?, Cl? or Br?ions, respectively, in the crystal. The formula of the admixture of the four most common endmembers is written as Ca10(PO4)6(OH, F, Cl, Br)2, and the crystal unit cell formulae of the individual minerals are written as Ca10(PO4)6(OH)2, Ca10(PO4)6(F)2, Ca10(PO4)6(Cl)2 and Ca10(PO4)6(Br)2. Apatite is one of few minerals that are produced and used by biological micro-environmental systems. Apatite has a Mohs Scale hardness of 5. Hydroxylapatite is the major component of tooth enamel. A relatively rare form of apatite in which most of the OH groups are absent and containing many carbonate and acid phosphate substitutions is a large component of bone material. Fluorapatite (or fluoroapatite) is more resistant to acid attack than is hydroxyapatite. For this reason, toothpaste typically contains a source of fluoride anions (e.g. sodium fluoride, sodium monofluorophosphate).

Данное издание не является оригинальным. Книга печатается по технологии принт-он-деманд после получения заказа.