INCORPORATION OF HYDROXYL IONS INTO CHLOR APATITE - CHARACTERIZATION BY INFRARED SPECTROMETRY (DIFFUSE-REFLECTANCE)

Synthetic chlorohydroxyapatites with high chlorine contents have been prepared hydrothermally according to the reaction: Ca-5(PO4)(3)(OH) x NH4 Cl with 0.4 less than or equal to x less than or equal to 1.2. T he infrared spectra of samples have been recorded and compared to the infrared spectra of flux-grown Clapatite crystals. These results show a new stretching vibration of the OH- ions in addition to those discov ered for the infrared transmission spectra of (OH,Cl) apatite samples. This new absorption band is at 3,595 cm(-1) for the high chlorine con tents in apatite series, and the intensity and the vibration frequenci es decrease as the OH- contents increase in the anion columns. Diffuse reflectance spectrometry is a good method to characterize OH- ions in the Clapatite series with x greater than or equal to 0.5.