High-resolution synchrotron X-ray powder diffraction and Rietveld structure refinement of two (Mg0.95,Fe0.05)SiO3 perovskite samples synthesized under different oxygen fugacity conditions

A. P. Jephcoat*, J. A. Hriljac, C. A. McCammon, H. St C O'Neill, D. C. Rubie, L. W. Finger

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

This paper presents high-resolution synchrotron X-ray powder diffraction data at 290 K on two Fe-bearing, polycrystalline silicate perovskite samples with approximate compositions (Mg0.95Fe0.05)SiO3 synthesized at 25 GPa and 1920 K in a multi-anvil press at different oxygen fugacity conditions. Mossbauer studies have indicated that Fe3+/ΣFe for the samples are 0.09 ± 0.01 and near 0.16 ± 0.03. Rietveld structural refinements confirm that Fe2+ and Fe3+ dominantly substitute for Mg2+ in the 8-fold to 12-fold coordinated A site for both compositions. There appears to be no significant differences in the bond distances for these amounts of Fe3+ and no conclusive structural evidence to support indications from Mossbauer experiments that Fe3+ may occupy both A and B sites. To explore the effect of valence state further, this study also reports the first diffraction patterns of (Mg,Fe)SiO3 perovskite collected at a wavelength near the Fe absorption edge.

Original languageEnglish
Pages (from-to)214-220
Number of pages7
JournalAmerican Mineralogist
Volume84
Issue number3
Publication statusPublished - Mar 1999
Externally publishedYes

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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