Apatites Fluorapatite and Hydroxyapatite

Impure fluorapatite, Caio(P04)g(F)2, is the main commercial source of phosphorus and its compounds, and impure hydroxyapatite Caio(P04)6(OH)2 is the main inorganic component of bones and teeth. These impure forms are better represented as francolite and dahlite, respectively (Table 2.6). 

Apatites can be represented by the formula Mio(X04)Y2, where M can be numerous metals or H3O+ X = P, As, Si, Ge, Mn, Cr, V, S, Se and so on, and Y = OH, F, Cl, Br, COj and so on. Solid solutions can be formed between many of these compounds. Only very recently has the successful synthesis of the iodide, Caio(P04)gl2 been reported, moreover it is believed that introduction of the radioactive isotope I may give a product with important medical uses [87]. 

Apatite was at one time confused with other hexagonal minerals and was so named from the Greek word apate meaning deceit. Although many cations and anions commonly substitute for Ca + and (P04) in mineral apatites, the degree of substitution is often insufficient to warrant naming a separate mineral species. 

Commonest Substitutions Found in Naturally Occurring Fluorapatites 

---