From the green color of eskolaite to the red color of ruby: an X-ray absorption spectroscopy study

Abstract : The best known cause for colors in insulating minerals is due to transition metal ions as impurities. As an example, Cr3+ is responsible for the red color of ruby (α-Al2O3:Cr3+) and the green color of eskolaite (α-Cr2O3). Using X-ray absorption measurements, we connect the colors of the Cr x Al2−x O3 series with the structural and electronic local environment around Cr. UV–VIS electronic parameters, such as the crystal field and the Racah parameter B, are related to those deduced from the analysis of the isotropic and XMCD spectra at the Cr L2,3-edges in Cr0.07Al1.93O3 and eskolaite. The Cr–O bond lengths are extracted by EXAFS at the Cr K-edge in the whole Cr x Al2−x O3 (0.07≤x< 2) solid solution series. The variation of the mean Cr–O distance between Cr0.07Al1.93O3 and α-Cr2O3 is evaluated to be 0.015 Å (≈1%). The variation of the crystal field in the Cr x Al2−x O3 series is discussed in relation with the variation of the averaged Cr–O distances.
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Article dans une revue
Physics and Chemistry of Minerals, Springer Verlag, 2006, 32, pp.710-720. <10.1007/s00269-005-0046-x>
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https://hal.archives-ouvertes.fr/hal-00112597
Contributeur : Danielle Thomas <>
Soumis le : jeudi 9 novembre 2006 - 11:42:38
Dernière modification le : lundi 29 mai 2017 - 14:35:48

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Emilie Gaudry, Philippe Sainctavit, Farid Juillot, Federica Bondioli, Philippe Ohresser, et al.. From the green color of eskolaite to the red color of ruby: an X-ray absorption spectroscopy study. Physics and Chemistry of Minerals, Springer Verlag, 2006, 32, pp.710-720. <10.1007/s00269-005-0046-x>. <hal-00112597>

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