Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-23T02:05:09.158Z Has data issue: false hasContentIssue false
  • English
  • Français

Reduction and Oxidation of Fe3+ in Dioctahedral Smectites — 1: Reduction with Hydrazine and Dithionite

Published online by Cambridge University Press:  01 July 2024

I. Rozenson  and
L. Heller-Kallai
I. Rozenson
Affiliation:
Dept. of Geology, Hebrew University, Jerusalem, Israel
L. Heller-Kallai
Affiliation:
Dept. of Geology, Hebrew University, Jerusalem, Israel
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.

Hydrazine and dithionite, both of which are strong reducing agents, react differently with various dioctahedral smectites. Both the nature of the reducing agent and the structure of the clay affect the course of the reaction. Hydrazine reduces octahedral Fe3+ efficiently if the mineral has a low tetrahedral charge. The reducing action of dithionite does not depend upon the charge.

The results obtained by different physical methods of investigation suggest that reduction of iron is associated with protonation of an adjacent OH group. The Fe2+ formed is readily re-oxidised but the structural changes occurring on reduction are reversible only when Al-OH-Fe, but not when Fe-OH-Fe associations are involved. Reaction mechanisms are proposed and changes in the distribution of iron in the octahedral sites are discussed.

Type
Research Article
Information
Clays and Clay Minerals , Volume 24 , Issue 6 , December 1976 , pp. 271 - 282
Copyright
Copyright © 1976 The Clay Minerals Society

References

Bancroft, G. M. (1974) Mössbauer spectroscopy. McGraw-Hill, New York.Google Scholar
Besson, G., Mifsud, A., Tchoubar, C. and Méring, J. (1974) Order and disorder relations in the distribution of the substitutions in smectites, illites and vermiculites: Clays & Clay Minerals 22, 379–384.CrossRefGoogle Scholar
Bystrom-Brusewitz, A. M. (1976) Studies on the Li test to distinguish between beidellite and montmorillonite: Proc. Intern. Clay Conf., Mexico (1975), 419–428.Google Scholar
Farmer, V. C. and Russell, J. D. (1964) The infra-red spectra of layer silicates: Spectrochim. Acta 20, 1149–1173.CrossRefGoogle Scholar
Fleet, M. E. (1974) Distortions in the coordination polyhedra of M site atoms in olivines, clinopyroxenes and amphiboles: Am. Miner. 59, 1083–1093.Google Scholar
Heller, L., Farmer, V. C., Mackenzie, R. C., Mitchell, B. D. and Taylor, H. F. W. (1962) The dehydroxylation and rehydroxylation of triphormic dioctahedral clay minerals: Clay Mineral. Bull. 28, 56–72.CrossRefGoogle Scholar
Heller-Kallai, L. (1976) Interaction of montmorillonite with alkali halides: Proc. Intern. Clay Conf., Mexico, (1975), 361–372.Google Scholar
Méring, J. and Oberlin, A. (1971) The smectites. In: Electron Optical Investigation of Clays (Ed. Gard, J. A.) Mineral. Soc., London, p. 193.CrossRefGoogle Scholar
Rozenson, I. (1975) Reduction-oxidation reactions in dioctahedral clays: M.Sc. thesis, Hebrew University, Israel (in Hebrew).Google Scholar
Roth, C. B. and Tullock, R. J. (1972) Deprotonation of nontronite resulting from chemical reduction of structural ferric iron: Proc. Intern. Clay Conf., Madrid (1972), 89–98.Google Scholar
Wardle, R. and Brindley, G. W. (1972) The crystal structure of pyrophyllite, ITc, and of its dehydroxylate: Am. Miner. 57, 732–750.Google Scholar