Complementary information on water and hydroxyl groups in nanocrystalline carbonated hydroxyapatites from TGA, NMR and IR measurements

A set of 10 nanocrystalline carbonated hydroxyapatites (CHA) was studied using TGA, NMR and IR methods. Particular attention has been directed on water and structural hydroxyl groups. Various their characteristics have been evaluated on the basis of mutual correlations. A new IR band at 587 cm−1 has been assigned to terminal PO 4 3 - groups on the crystal surface. The formerly noticed IR band at 670 cm−1 has been attributed to the librational mode of adsorbed water. It is recommended to use jointly different analytical methods in order to gain accurate knowledge on the CHA materials.