Hostname: page-component-78c5997874-4rdpn Total loading time: 0 Render date: 2024-11-14T13:24:30.277Z Has data issue: false hasContentIssue false

Phase transitions in hydroxide perovskites: a Raman spectroscopic study of stottite, FeGe(OH)6, to 21 GPa

Published online by Cambridge University Press:  05 July 2018

A. K. Kleppe*
Affiliation:
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
M. D. Welch
Affiliation:
Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
W. A. Crichton
Affiliation:
European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, Grenoble Cedex, F-38043, France
A. P. Jephcoat
Affiliation:
Department of Earth Sciences University of Oxford, South Parks Road, Oxford OX1 3AN, UK
*

Abstract

The effect of pressure on the naturally occurring hydroxide-perovskite stottite, FeGe(OH)6, has been studied in situ by micro-Raman spectroscopy to 21 GPa at 300 K. The ambient spectrum contains six OH-stretching bands in the range 3064 3352 cm–1. The presence of six non-equivalent OH groups is inconsistent with space group P42/n. In view of this inconsistency a new ambient structure determination of stottite from Tsumeb was carried out, but this did not allow the clear rejection of P42/n symmetry. However, a successful refinement was also carried out in space group P2/n, a subgroup of P42/n, which allows for six non-equivalent O atoms. The two refinements are of comparable quality and do not allow a choice to be made based purely on the X-ray data. However, taken with the ambient and 150 K Raman spectra, a good case can be made for stottite having P2/n symmetry at ambient conditions. On this basis, the pressure induced spectroscopic changes are interpreted in terms of a reversible phase transition P2/nP42/n.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Basciano, L.C., Peterson, R.C. and Roeder, P.L. (1998) Description of schoenfliesite, MgSn(OH)6, and roxbyite, Cu1 72S, from a 1375 BC shipwreck, and Rietveld neutron-diffraction refinement of synthetic schoenfliesite, wickmanite, MnSn(OH)6, and burtite, CaSn(OH)6 . The Canadian Mineralogist, 36, 12031210.Google Scholar
Birch, W.D., Pring, A., Reller, A. and Schmalle, H.W. (1993) Bernalite, Fe(OH)3, a new mineral from Broken Hill, New South Wales: description and structure. American Mineralogist, 78, 827834.Google Scholar
Jephcoat, A.P., Mao, H.K. and Bell, P.M. (1987) Operation of the Megabar Diamond-Anvil Cell. Hydrothermal Experimental Techniques, 19, 469506.Google Scholar
Matsui, M., Komatsu, K., Ikeda, E., Sano-Furukawa, A., Gotou, H. and Yagi, T. (2011) The crystal structure of 5-Al(OH)3: neutron diffraction measurements an. ab initio calculations. American Mineralogist, 96, 854859.CrossRefGoogle Scholar
Robinson, K., Gibbs, G.V. and Ribbe, P.H. (1971) Quadratic elongation: a quantitative measure of distortion in coordination polyhedra. Science, 172, 567570.CrossRefGoogle ScholarPubMed
Ross, C.R. II, Bernstein, L.R. and Waychunas, GA. (1988) Crystal-structure refinement of stottite, FeGe(OH)6 . American Mineralogist, 73, 657661.Google Scholar
Ross, N.L., Chaplin, T.D. and Welch, M.D. (2002) Compressibility of stottite, FeGe(OH)6: an octahedral framework with protonated O atoms. American Mineralogist, 87, 14101414.CrossRefGoogle Scholar
Ross, N.L., Zhao, J., Burt, J.D. and Chaplin, T.D. (2004) Equations of state of GdFeO3 and GdAlO3perovskites. Journal of Physics, Condensed Matter, 16, 57215730.CrossRefGoogle Scholar
Sheldrick, GM. (2008) A short history of SHELX. Acta Crystallographica, A64, 112122.CrossRefGoogle Scholar
Spek, A.L. (2005) PLATON, A multipurpose crystal-lographic tool. Utrecht University, Utrecht, The Netherlands.Google Scholar
Strunz, H. and Giglio, M. (1961) Die Kristallstruktur von Stottite, Fe[Ge(OH)6]. Acta Crystallographica, 14, 205208.CrossRefGoogle Scholar
Strunz, H., Sohnge, G and Geier, B. H. (1958) Stottite, ein neues Germanium-Mineral und seine Paragenese in Tsumeb. Neues Jahrbuch fur Mineralogie Monatshefte, 1958, 8596.Google Scholar
Welch, M.D. and Wunder, B. (in press) A single-crystal X-ray diffraction study of the 3.65 A-phase MgSi(OH)6, a high-pressure hydroxide perovskite. Physics and Chemistry of Minerals, http://dx.doi.org/10.1007/s00269-012-0523-y.CrossRefGoogle Scholar
Welch, M.D., Crichton, WA. and Ross, N.L. (2005) Compression of the perovskite-related mineral bernalite Fe(OH)3 to 9 GPa and a reappraisal of its structure. Mineralogical Magazine, 69, 309315.CrossRefGoogle Scholar
Williams, SA. (1985) Mopungite, a new mineral from Nevada. Mineralogical Record, 16, 7374.Google Scholar
Wunder, B., Wirth, R. and Koch-Miiller, M. (2011) The 3.65 A phase in the system MgO-SiO2-H2O: synthesis, composition, and structure. American Mineralogist, 96, 12071214.CrossRefGoogle Scholar
Wunder, B., Jahn, S., Koch-Miiller, M. and Speziale, S. (2012) The 3.65 A phase, MgSi(OH)6: structural insights from DFT calculations and T-dependent IR spectroscopy. American Mineralogist, 97, 10431048.CrossRefGoogle Scholar
Zhao, J., Ross, N.L. and Angel, R.J. (2004) A new view of the high-pressure behaviour of GdFeO3-type perovskites. Acta Crystallographica, B60, 263271.CrossRefGoogle Scholar