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Mössbauer effect study on the mixed valence state of iron in tourmaline

Published online by Cambridge University Press:  05 July 2018

E. A. Ferrow
Affiliation:
Department of Mineralogy and Petrology, University of Lund, Sölvegatan 13, S-222 62 Lund, Sweden
H. Annersten
Affiliation:
Department of Mineralogy and Petrology, University of Uppsala, Box 555, S-751 22 Uppsala, Sweden
R. P. Gunawardane
Affiliation:
Department of Chemistry, University of Paradeniya, Paradeniya, Sri Lanka

Abstract

Mössbauer spectra of iron-bearing tourmaline, obtained at different temperatures, show the existence of thermally-activated charge delocalization among clusters of iron atoms situated in the Y and Z octahedra of the tourmaline structure. The temperature dependence indicates an unusually high activation energy for the delocalization process which suggests that the process takes place between crystallographically non-equivalent sites. Annealing of the tourmaline in hydrogen is observed to inhibit the delocalization process, thus localizing the electron into the Z-site.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1988

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