Abstract
Six schorlomite samples with TiO2 contents varying between 9.70 and 15.34 weight percent were studied by means of Mössbauer spectroscopy and chemical analysis. The measured Mössbauer spectra have complex shapes. The spectra of these samples were fitted with six doublets, which can be assigned to VIIIFe2+, VIFe2+, VIFe3+, IVFe3+ and two electron delocalizations, IVFe3+ ⇌ VIIIFe2+ and IVFe3+ ⇌ VIFe2+, respectively. The assignment of iron absorption doublets and their Mössbauer parameters are discussed in terms of the single crystal structure data of one of the samples studied in this work. Cation distributions are also given. The occupancies of cations at the tetrahedral (Z) site are Fe3+>Al3+, Ti4+, and the relative enrichments at Z site are always Fe3+>Ti4+. Most of the six samples contain Ti3+. Ti3+/ΣTi ratios range from 1.43 percent to 6.40 percent. Fe2+/ΣFe ratios vary from 8.84 percent to 11.31 percent. Four types of substitution must be considered for Ti entering the garnet structure.
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Gongbao, W., Baolei, M. The crystal chemistry and mössbauer study of schorlomite. Phys Chem Minerals 13, 198–205 (1986). https://doi.org/10.1007/BF00308162
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DOI: https://doi.org/10.1007/BF00308162