[FTIR investigation on crystal chemistry of CO(2-)3-substituted apatite solid solutions prepared through different...

The CO(2-)3-substituted apatite solid solutions were prepared through different methods. The FTIR and XRD measurements were applied to investigate its crystal chemistry properties. The results indicated that the CO(2-)3-substituted sites in the carbonate hydroxyapatite(CHAP) prepared through homogeneous precipitation method are type-B in which [CO3.OH] tetrahedral-coordinations are substituted for [PO4] tetrahedral-coordinations; the ones in the CHAP prepared through solid phase ions exchange method are type-A in which [CO3] triangle-coordinations are substituted for [OH] in column sites; the ones in the carbonate fluorapatite(CFAP) prepared through solid phase reaction method are type-B in which [CO3.F] tetrahedral-coordinations are substituted for [PO4] tetrahedral-coordinations; the ones in the CHAP prepared through sol-gel method are AB mixed-type. The vibrational band psi 3 is splitted into psi 3-1, psi 3-4 and psi 3F. The psi 3F is combined by psi 3-2 (type-A) and psi 3-3 (type-B) in Gaussian function fitting. When Wco(2-)3 < 3.34%, substitution value of type-A increases with the increasing of CO(2-)3 contents. When Wco(2-)3 = 3.34%, substitution value of type-A has maximum. When 3.34% < Wco(2-)3 < 7.52%, substitution value of type-B increases with the increasing of CO(2-)3 contents. When Wco(2-)3 = 7.52%, substitution value of type-B has maximum.