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Verification of the Triclinic Crystal Structure of Kaolinite

Published online by Cambridge University Press:  02 April 2024

R. A. Young  and
A. W. Hewat
R. A. Young
Affiliation:
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332
A. W. Hewat
Affiliation:
Institut Max von Laue, Paul Langevin, B.P. 156X, Centre de Tri, 38042 Grenoble Cedex, France
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Abstract

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On the basis of neutron diffraction studies, the two inner-hydroxyl ions in highly ordered kaolinite were recently shown to be differently oriented. One of the inner-hydroxyl ions points generally toward a hole in the octahedral sheet and the other toward a hole in the tetrahedral sheet. These orientations and the locations of the other atoms in the primitive triclinic unit cell have now been determined for a sample of Keokuk kaolinite with improved precision compared with that reported earlier. Rietveld structure refinement was carried out for the entire crystal structure simultaneously (99 atom positional and 17 other parameters) with each of two newly collected sets of high-resolution neutron powder diffraction data. The different orientations of the inner-hydroxyl ions are the most marked evidence that the unit cell is not C centered. The positions of the inner-surface hydrogen atoms provide further evidence in that all differ from a C-centered relationship by six to eight estimated standard deviations in their y coordinates. The cell is, therefore, not centered. The space group is P1.

Keywords

Inner hydroxylKaoliniteNeutron powder diffractionRietveld structure refinementTriclinicity
Type
Research Article
Information
Clays and Clay Minerals , Volume 36 , Issue 3 , June 1988 , pp. 225 - 232
Copyright
Copyright © 1988, The Clay Minerals Society

References

Adams, J. M., 1983 Hydrogen atom positions in kaolinite by neutron profile refinement Clays & Clay Minerals 31 352 – 356.CrossRefGoogle Scholar
Adams, J. M. and Hewat, A. W., 1981 Hydrogen atom positions in dickite Clays & Clay Minerals 29 316 – 319.CrossRefGoogle Scholar
Brindley, G. W. and Robinson, K., 1946 The structure of kaolinite Mineral. Mag. 31 781 – 786.Google Scholar
Hayes, J. B., 1963 Kaolinite from Warsaw geodes, Keokuk region, Iowa Iowa Acad. Sci. 70 261 – 272.Google Scholar
Hewat, A. W., 1973 The Rietveld computer program for profile refinement of neutron powder diffraction patterns modified for anisotropic thermal vibration Harwell Report AERE-R7350 .Google Scholar
Hewat, A. W. and Bailey, A., 1976 D1 A. A high-resolution neutron powder diffractometer with a bank of mylar collectors Nuclear Instruments and Methods 137 463 – 471.CrossRefGoogle Scholar
Howard, C. J., 1981 The approximation of asymmetric neutron powder diffraction peaks by sums of gaussians J. Appl. Crystallogr. 15 615 – 620.CrossRefGoogle Scholar
Keller, W. D., Pickett, E. E., Reesman, A. L., Heller, L. and Weiss, A., 1966 Elevated dehydroxylation temperature of the Keokuk geode kaolinite—A possible reference mineral Proc. Inter. Clay Conf., Jerusalem, 1966, Vol. 1 Jerusalem Israel Prog. Sci. Transi. 75 – 85.Google Scholar
ORFFE4, 1985 ORFFE4 crystallographic function and error program Oak Ridge, Tennessee Oak Ridge National Laboratory.Google Scholar
Plançon, A. and Tchoubar, C., 1975 Etude des fautes d’empilement dans les kaolinites partiellement désordonnées. I. Modèle d’empilement ne comportant que des fautes de translation J. Appl. Crystallogr. 8 582 – 588.CrossRefGoogle Scholar
Plançon, A. and Tchoubar, C., 1977 Determination of structural defects in phyllosilicates by X-ray powder diffraction. II. Nature and proportion of defects in natural kaolinites Clays & Clay Minerals 25 436 – 450.CrossRefGoogle Scholar
Reynolds, R. C. Jr., 1983 Calculation of absolute intensities for mixed-layered clays Clays & Clay Minerals 31 233 – 234.CrossRefGoogle Scholar
Rietveld, H. M., 1969 Profile refinement method for nuclear and magnetic structures J. Appl. Crystallogr. 2 65 – 71.CrossRefGoogle Scholar
Suitch, P. R. and Young, R. A., 1983 Atom positions in well-ordered kaolinite Clays & Clay Minerals 31 357 – 366.CrossRefGoogle Scholar
Tchoubar, C., 1984 X-ray structural studies of defects in clays Phil. Trans. Royal Soc. London A 311 259 – 269.Google Scholar
Thompson, J. G., 1984 Two possible interpretations of Si nuclear magnetic resonance spectra of kaolin group minerals Clays & Clay Minerals 32 233 – 234.CrossRefGoogle Scholar
Thompson, J. G. and Withers, R. L., 1987 A transmission electron microscope contribution to the structure of kaolinite Clays & Clay Minerals 35 237 – 239.CrossRefGoogle Scholar
Wiles, D. B. and Young, R. A., 1981 New computer program for Rietveld analysis of X-ray powder diffraction patterns J. Appl. Crystallogr. 14 149 – 151.CrossRefGoogle Scholar
Young, R.A., 1988 Pressing the limits of Rietveld structure refinement Australian J. Physics .CrossRefGoogle Scholar
Young, R. A. and Wiles, D. B., 1981 Application of the Rietveld method for structure refinement with powder diffraction data Adv. X-ray Analysis 24 1 – 23.Google Scholar