High-resolution synchrotron X-ray powder diffraction and Rietveld structure refinement of two (Mg{sub 0.95},Fe{sub 0.5})SiO{sub 3} perovskite samples synthesized under different oxygen fugacity conditions
- Univ. of Oxford (United Kingdom). Dept. of Earth Sciences
- Brookhaven National Lab., Long Island, NY (United States)
- Univ. Bayreuth (Germany). Bayerisches Geoinstitut
- Carnegie Institution of Washington, DC (United States)
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 (Mg{sub 0.95}Fe{sub 0.05})SiO{sub 3} synthesized at 25 GPa and 1920 K in a multi-anvil press at different oxygen fugacity conditions. Rietveld structural refinements confirm that Fe{sup 2+} and Fe{sup 3+} dominantly substitute for Mg{sup 2+} 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 Fe{sup 3+} and no conclusive structural evidence to support indications from Moessbauer experiments that Fe{sup 3+} 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)SiO{sub 3} perovskite collected at a wavelength near the Fe absorption edge.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- North Atlantic Treaty Organization, Brussels (Belgium); Royal Society, London (United Kingdom); Natural Environment Research Council, London (United Kingdom); National Science Foundation, Washington, DC (United States); USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 328316
- Journal Information:
- American Mineralogist, Vol. 84, Issue 3; Other Information: PBD: Mar 1999
- Country of Publication:
- United States
- Language:
- English
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