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Analysis and Implications of the Edge Structure of Dioctahedral Phyllosilicates

Published online by Cambridge University Press:  02 April 2024

G. Norman White  and
L. W. Zelazny
G. Norman White
Affiliation:
Department of Agronomy, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
L. W. Zelazny
Affiliation:
Department of Agronomy, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
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Abstract

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Crystal growth theory was applied to describe edge sites of phyllosilicates. Three face configurations were found to exist. One face has one tetrahedral site per tetrahedral sheet and two octahedral one-coordinated sites per crystallographic area ac sin β, where a and c are layer dimensions and β is the angle between them. The other two faces are similar except that they have one less octahedral site which is replaced by one SiIV-O-AlVI site in this same ac sin β area. A transfer of bonding energy from the remaining octahedral site to the SiIV-O-AlVI site is believed to neutralize all edge charge on faces containing these latter sites at normally encountered pHs (pH 3–9). A similar charge rearrangement along the edges results in an apparent decrease in the permanent charge of the mineral with an increase in edge area.

On the basis of such an analysis, lath-shaped illite can be described as a very fine grained dioctahedral mica in which the apparent deficient occupancy of the octahedral sheet, presence of excess water, and measurable cation-exchange capacity may in part be the result of a large ratio of edge area to total volume, with no other chemical or structural change in the mica layers. The increasing importance of edge charge relative to layer charge produces erroneous formulae for 2:1 phyllosilicates in very fine grained samples containing fewer than 2 of 3 octahedral sites occupied by cations, on the basis of a 22-charge half cell.

Keywords

CeladoniteEdge structureIlliteMuscoviteOctahedral sitePhengite
Type
Research Article
Information
Clays and Clay Minerals , Volume 36 , Issue 2 , April 1988 , pp. 141 - 146
Copyright
Copyright © 1988, The Clay Minerals Society

References

Bailey, S. W., Bailey, S. W., Brindley, G. W., Keller, W. D., Wones, D. R. and Smith, J. V., 1967 Polytypism of layer silicates AGI Short Course Lecture Notes on Layer Silicates Washington, D.C. Amer. Geol. Inst.Google Scholar
Berner, R. A., 1971 Principles of Chemical Sedimentology New York McGraw-Hill.Google Scholar
Grim, R. E. and Güven, N., 1978 Bentonites: Geology, Mineralogy, Properties, and Uses New York Elsevier.Google Scholar
Güven, N., 1980 The crystal structures of 2M 1 phengite and muscovite Z Kristallogr. 134 196 – 212.Google Scholar
Güven, N., Hower, W. F. and Davies, D. K., 1980 Nature of authigenic illites in sandstone reservoirs J. Sed. Petrol. 50 761 – 766.Google Scholar
Hartman, P., 1963 Structure, growth and morphology of crystals Z. Kristallogr. 119 65 – 78.CrossRefGoogle Scholar
Hartman, P. and Hartman, P., 1973 Structure and morphology Crystal Growth: An Introduction Amsterdam North-Holland Publ. 367 – 402.Google Scholar
Hartman, P., 1978 On the validity of the Donnay-Harker Law Can. Mineral. 16 387 – 391.Google Scholar
Hartman, P., 1982 On the growth of dolomite and kaolinite crystals N. Jb. Miner. Mh. 1982 84 – 92.Google Scholar
Jackson, M. L. and Bear, F. E., 1964 Chemical composition of soils Chemistry of the Soil New York Reinhold 71 – 141.Google Scholar
Langmuir, D., Whittemore, D. O. and Gould, R. F., 1971 Variations in the stability of precipitated ferric oxyhydroxides Non-equilibrium Systems in Natural Water Chemistry 209 – 234.CrossRefGoogle Scholar
Lee, J. H. and Guggenheim, S., 1981 Single crystal X-ray refinement of pyrophyllite-1 Te: Amer. Mineral. 66 350 – 357.Google Scholar
Muljadi, D., Posner, A. M. and Quirk, J. P., 1966 The mechanism of phosphate adsorption by kaolinite, gibbsite, and pseudoboehmite J. Soil Sei. 17 212 – 247.CrossRefGoogle Scholar
Nadeau, P. H., Tait, J. M., McHardy, W. J. and Wilson, M. J., 1984 Interstratified XRD characteristics of physical mixtures of elementary clay particles Clay Miner. 19 67 – 76.CrossRefGoogle Scholar
Nadeau, P. H., Wilson, M. J., McHardy, W. J. and Tait, J. M., 1984 Interstratified clays as fundamental particles Science 225 923 – 925.CrossRefGoogle ScholarPubMed
Preisinger, A. and Swineford, A., 1959 X-ray study of the structure of sepiolite Clays and Clay Minerals, Proc. 6th Natl. Conf., Berkeley, California, 1957 New York Pergamon Press 61 – 67.Google Scholar
Schofield, R. D. and Samson, H. R., 1953 The deflocculation of kaolinite suspensions and the accompanying change over from positive to negative chloride adsorption Clay Miner. Bull. 2 45 – 51.CrossRefGoogle Scholar
Środoń, J., Morgan, D. J., Eslinger, E. V., Eberl, D. D. and Karlinger, M. R., 1986 Chemistry of illite/smectite and end-member illite Clays & Clay Minerals 34 368 – 378.CrossRefGoogle Scholar
Stum, W. and Morgan, J. J., 1981 Aquatic Chemistry New York John Wiley.Google Scholar
Weaver, C. E. and Pollard, L. D., 1973 The Chemistry of Clay Minerals New York Elsevier.Google Scholar