Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-14T23:20:15.717Z Has data issue: false hasContentIssue false
  • English
  • Français

A Mössbauer study of thermal decomposition of biotites

Published online by Cambridge University Press:  05 July 2018

C. S. Hogg  and
R. E. Meads
C. S. Hogg
Affiliation:
Research Laboratories, English Clays, Lovering, Pochin & Co. Ltd., St. Austell, Cornwall
R. E. Meads
Affiliation:
Research Laboratories, English Clays, Lovering, Pochin & Co. Ltd., St. Austell, Cornwall
Get access Rights & Permissions [Opens in a new window]

Summary

The effect of heat treatment in air at temperatures from 200°C to 1000°C of two Cornish biotites has been studied using the M6ssbauer effect in 57Fe. One of the micas was also studied after heating in vacuo.

Progressive changes in the Mössbauer spectra of the materials after heat treatment can be correlated with the following processes: Oxidation of Fe2+ ions in isolated octahedral sites to give Fe3+ in the co-ordination Fe3+(OsOH); oxidation of Fe2+ ions in adjacent a-octahedral (cis OH−) sites to give Fe3+(O6); and oxidation of Fe z+ in adjacent a and b (trans OH−) sites to give either Fe3+(O5OH) or Fe3+(O6) depending on whether a shared hydroxyl group remains intact or otherwise (these processes occur at temperatures below 500°C Also, at higher temperatures, dehydroxylation of Fe3+(O5OH) to give more Fe3+ in the Fe3+(O6) configuration. Finally, in the temperature range 900 to 1000°C structural breakdown yielding α-Fe2O3 as the iron-containing phase.

The results and interpretation are in good agreement with thermogravimetric data and with a previous infra-red study. The mechanism of charge diffusion in the lattice during oxidation is discussed in the light of the results.

Type
Research Article
Information
Mineralogical Magazine , Volume 40 , Issue 309 , March 1975 , pp. 79 - 88
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1975

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

Addison, (C. C.), Addison, (W. E.), Neal, (G. H.), and Sharp, (J. H.), 1962. Journ. Chem. Soc., 1468.CrossRefGoogle Scholar
Annersten, (H.), 1974. Amer. Min. 59, 143.Google Scholar
Annersten, (H.), Devanarayanan, (S.), Häggström, (L.), and Wäppling, (R.), 1971. Phys. Stat. Sol. 48b, K137.CrossRefGoogle Scholar
Bancroft, (G. M.), 1973. MöSssbauer spectroscopy—an introduction for inorganic chemists and geochemists, London (McGraw-Hill), 186.Google Scholar
Bernal, (J. D.), Dasgupta, (D. R.), and Mackay, (A. L.), 1959. Clay Min. Bull. 4, 15.CrossRefGoogle Scholar
Brindley, (G. W.), 1963. Prog. Ceram. Sci. 3, 1.Google Scholar
Davidson, (A. T.) and Yoree, (A. D.), 1968. Phys. Stat. Solid, 30, 741.CrossRefGoogle Scholar
Gibb, (T. C.) and Greenwood, (N. N.), 1965. Trans. Farad. Soc. 61, 1317.CrossRefGoogle Scholar
Goodman, (B. A.) and Wilson, (M. J.), 1973. MiD. Mag. 39, 448.CrossRefGoogle Scholar
Häggström, (L.), Wäppling, (R.), and Annersten, (H.), 1969. Chem. Phys. Letters, 4, 107.CrossRefGoogle Scholar
Hellner, (E.) and Euler, (R.), 1957. Geochimica Acta 12, 47.CrossRefGoogle Scholar
Hodgson, (A. A.), Freeman, (A. G.), and Taylor, (H. F. W.), 1965a. Min. Mag. 35, 5.Google Scholar
Hodgson, (A. A.), Freeman, (A. G.), and Taylor, (H. F. W.), 1965b. Min. Mag. 35, 445.Google Scholar
Hogarth, (D. D.), Brown, (F. F.), and Pritchard, (A. M.), 1970. Can. Mineral. 10, 710.Google Scholar
Hogg, (C. S.) and Meads, (R. E.), 1970. Min. Mag. 37, 606.CrossRefGoogle Scholar
Kemp, (R. C.), 1972. Journ. Phys. C. (Solid State Phys.), 5, 3566.CrossRefGoogle Scholar
Littler, (J. G. F.) and Williams, (R. J. P.), 1965. Journ. Chem. Soc., 6368.CrossRefGoogle Scholar
Mackenzie, (K. J. D.), 1969. Clay Minerals 8, 151.CrossRefGoogle Scholar
Rice, (C. M.) and Williams, (J. M.), 1969. Min. Mag. 37, 210.CrossRefGoogle Scholar
Redder, (W.) and Wilkins, (R. W. T.), 1969. Amer. Min. 54, 482.Google Scholar
Yassoglou, (N. J.), Nobeli, (C.), Kostikas, (A. J.), and Simopoulos, (A. C.), 1972. Soil Sci. Soc. Amer. Proc. 36, 520.CrossRefGoogle Scholar