Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-22T19:18:08.487Z Has data issue: false hasContentIssue false
  • English
  • Français

57Fe Mössbauer Spectroscopy of Montmorillonites: A New Interpretation

Published online by Cambridge University Press:  02 April 2024

C. M. Cardile  and
J. H. Johnston
C. M. Cardile
Affiliation:
Chemistry Department, Victoria University of Wellington, Private Bag, Wellington, New Zealand
J. H. Johnston*
Affiliation:
Chemistry Department, Victoria University of Wellington, Private Bag, Wellington, New Zealand
*
1To whom all correspondence should be addressed.
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The 57Fe Mössbauer spectra of several montmorillonites, measured at room temperature and 453 K, showed a considerably broadened Fe3+ resonance which can be computer-fitted with a similarly broadened Fe3+ doublet. In some spectra, particularly if all linewidths were constrained to be equal, this broadened Fe3+ resonance was further resolved into overlapping inner and outer Fe3+ doublets, also having broad linewidths. In accordance with recent electron diffraction evidence, the assignment by previous workers of the inner doublet to Fe3+ in the octahedral sites having the cis-arrangement of OH groups and the outer doublet to the octahedral site having the trans-arrangement of OH groups is incorrect. Instead, the Fe3+ was found to be located largely in the trans-octahedral sites. Because of the relatively low iron content of the montmorillonite examined, the next and more distant neighboring-cation environment varied considerably about the octahedral Fe3+ ions. This variation produced a broadened experimental resonance, and the resulting two-doublet computer fits probably represent the mean extremes of a continuum of slightly different Fe3+ resonances arising from the variable nature of the environment surrounding these such trans-sites, rather than distinct cis- and trans-sites. In addition, a small resonance indicating the substitution of Fe3+ into the tetrahedral sites was observed. The interlayer species probably influenced the Mössbauer resonance of Fe3+ in the tetrahedral and octahedral sites.

Keywords

IronMontmorilloniteMössbauer spectroscopyOctahedral sitesTetrahedral sites
Type
Research Article
Information
Clays and Clay Minerals , Volume 34 , Issue 3 , June 1986 , pp. 307 - 313
Copyright
Copyright © 1986, The Clay Minerals Society

References

Bancroft, G. M., 1973 Mössbauer Spectroscopy: An Introduction for Inorganic Chemists and Geochemists London McGraw-Hill.Google Scholar
Besson, G., Bookin, A. S., Dainyak, L. G., Rautureau, M., Tsipursky, S. I., Tchoubar, C. and Drits, V. A., 1983 Use of diffraction methods for structural and crystallochemical characterisation of nontronite J. Appl. Crystallogr. 16 374–383.CrossRefGoogle Scholar
Brindley, G. W. and Brown, G., 1980 Crystal Structures of Clay Minerals and Their X-ray Identification London Mineralogical Society.CrossRefGoogle Scholar
Cardile, C. M. and Johnston, J. H., 1985 Structural studies of nontronite with different iron contents by 57Fe Mössbauer spectroscopy Clays & Clay Minerals 33 295–300.CrossRefGoogle Scholar
Dickson, D. P. E. and Cardile, C. M., 1985 Magnetic ordering in a montmorillonite observed by 57Fe Mössbauer spectroscopy at 1.3 K Clays & Clay Minerals 34 103–104.CrossRefGoogle Scholar
Drits, V. A., Plançon, A., Sakharov, B. A., Besson, G., Tsipursky, S. I. and Tchoubar, C., 1984 Diffraction effect calculated for structural models of K-saturated montmorillonite containing different types of defects Clay Miner. 19 541–561.Google Scholar
Goodman, B. A., 1978 The Mössbauer spectra of nontronites: consideration of an alternative assignment Clays & Clay Minerals 26 176–177.CrossRefGoogle Scholar
Helsen, J. A. and Goodman, B. A., 1983 Characterization of iron(II)- and iron(III)-exchanged montmorillonite and hectorite using the Mössbauer effect Clays & Clay Minerals 18 117–125.CrossRefGoogle Scholar
Johnston, J. H. and Cardile, C. M., 1985 Iron sites in nontronite and the effect of interlayer cations from Mössbauer spectra Clays & Clay Minerals 33 21–30.CrossRefGoogle Scholar
Johnston, J. H. and Lewis, D. G., 1983 A study of the transformation of ferrihydrite to hematite in an aqueous medium at 92°C Geochim. Cosmochim. Acta 47 1823–1831.CrossRefGoogle Scholar
Johnston, J. H. and Lewis, D. G., 1986 A study of the initially-formed hydrolysis species and intermediate polymers and their role in determining the product iron oxides formed in the weathering of iron Proc. Industrial Applications of the Mössbauer Effect, Hawaii, 1984 New York Plenum.Google Scholar
Mering, J., Oberlin, A. and Bailey, S. W., 1967 Electron-optical studies of smectites Clays and Clay Minerals, Proc. 15th Natl. Conf., Pittsburgh, Pennsylvania, 1966 New York Pergamon Press 3–25.Google Scholar
Rozenson, I. and Heller-Kallai, L., 1977 Mössbauer spectra of dioctahedral smectites Clays & Clay Minerals 25 94–101.CrossRefGoogle Scholar
Tsipursky, S. I. and Drits, V. A., 1984 The distribution of octahedral cations in the 2:1 layers of dioctahedral smectites studied by oblique-texture electron diffraction Clay Miner. 19 177–193.CrossRefGoogle Scholar