Electron paramagnetic resonance spectral studies on natural sapphire

Abstract

EPR study of both blue and green sapphire samples confirms the presence of Cr(III) in four different octahedral sites. The g (1.98) value is the same but D values differ for the two the samples. The EPR spectra suggest that the blue sapphire contains more chromium than the green sapphire. No Fe(III) impurity was noted in the EPR spectrum

Keywords:

• sapphire
• EPR spectra
• octahedral symmetry
• Cr ions

Acknowledgements

The authors wish to express their sincere thanks to Dr Lock V. Dunog, Department of Chemistry, Queensland University, Queensland, Australia for generously donating sapphire mineral samples. Thanks are also due to Professor P.S. Rao, Professor of Chemistry, Pondicherry University, Pondicherry, India for providing EPR facility.