Infrared spectra of carbonate apatites: v2-Region bands.
The proportions of A and B carbonate ions in a selection of AB carbonate apatites, including hydroxyapatite (CHAP), chlorapatite (CCLAP) and fluorapatite (CFAP), have been obtained using the out-of-plane bend (nu(2)) bands of Fourier transform infrared (FTIR) spectra. Band area ratios (B/A) are in very good agreement with site occupancies from single-crystal X-ray structure refinement; the correlation is linear (1:1) for B/A values ranging up to three. Most compositions have nu(2) spectra with one band for A carbonate (at 878-880 cm(-1)) and one for B (at 870-872 cm(-1)). Na-free AB CHAP has a third prominent band at 862 cm(-1), which is assigned to the stuffed channel species (A2), and Na-bearing CFAP has a third band at 864 cm(-1), which is assigned to a second B carbonate environment (B2). The A2 and B2 assignments are based largely on spectral changes in annealed samples.
Fleet
Michael E
ME
Department of Earth Sciences, University of Western Ontario, Richmond Street, London, Ontario, Canada. mfleet@uwo.ca
D001031:Apatites / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry*; D016011:Normal Distribution; D012964:Sodium / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
D001031:Apatites; D002254:Carbonates; D012964:Sodium