Local relaxation in lanthanum silicate oxyapatites by Raman scattering and MAS-NMR
Article first published online: 23 FEB 2011
Copyright © 2011 John Wiley & Sons, Ltd.
Journal of Raman Spectroscopy
Volume 42, Issue 6, pages 1455–1461, June 2011
How to Cite
Guillot, S., Beaudet-Savignat, S., Lambert, S., Roussel, P., Tricot, G., Vannier, R.-N. and Rubbens, A. (2011), Local relaxation in lanthanum silicate oxyapatites by Raman scattering and MAS-NMR. J. Raman Spectrosc., 42: 1455–1461. doi: 10.1002/jrs.2878
- Issue published online: 17 JUN 2011
- Article first published online: 23 FEB 2011
- Manuscript Accepted: 29 NOV 2010
- Manuscript Received: 23 SEP 2010
- lanthanum silicate;
- Raman scattering;
- 29Si MAS-NMR;
- 27Al MAS-NMR
To characterize the local relaxation in the structure of lanthanum silicate oxyapatite materials, six compositions with different cation and oxygen stoichiometries (La8Ba2Si6O26, La9BaSi6O26.5, La10Si5.5Mg0.5O26.5, La9.33SiO26, La9.67SiO26.5 and La9.83Si5.5Al0.5O26.5) were investigated by combining Raman scattering and 29Si and 27Al magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopies. Only [SiO4]4− species were evidenced and the hypotheses of [Si2O7]6− and [Si2O9]8− entities were ruled out. Both oxygen excess and cation vacancies induce local distortions in the structure, which leads to nonequivalent [SiO4]4− species, characterized by different 29Si MAS-NMR signals and by splitting of Raman signals. Copyright © 2011 John Wiley & Sons, Ltd.