A new method of preparation of solid solutions of calcium-cadmium-lead hydroxylapatite and their characterization by X-ray, electronmicrography and IR spectra

Abstract

Solid solutions of calcium-cadmium-lead hydroxylapatites have been prepared in aqueous media at <em>p</em>H<em> ~ </em>12. The samples have been characterised by analysis, X-ray, electronmicroscopy and infra red spectra. The site occupancy of the cations in the apatite lattice and order- disorder phenomena has been discussed. Existance of hydrogen bond mechanism originating from OH stretching frequency in the IR spectra of the apatites is discussed. It is observed that for high values of substitution of cations, the OH group frequency becomes very weak due to the progressive decrease in the polarization power of calcium, cadmium and lead. The point group of the tetrahedral PO<img src='http://www.niscair.res.in/jinfo/minusthree.gif' border=0> ion is found to depend on the proportion of the cation substituted in calcium hydroxylapatite.