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Neutron Diffraction Study of a One-Layer Monoclinic Chlorite

Published online by Cambridge University Press:  02 April 2024

Werner Joswig ,
Hartmut Fuess  and
Sax A. Mason
Werner Joswig
Affiliation:
Institut für Kristallographie und Mineralogie, Universität Frankfurt, D6000 Frankfurt am Main, Federal Republic of Germany
Hartmut Fuess
Affiliation:
Institut für Kristallographie und Mineralogie, Universität Frankfurt, D6000 Frankfurt am Main, Federal Republic of Germany
Sax A. Mason
Affiliation:
Institute Laue-Langevin, Grenoble, France
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Abstract

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A monoclinic IIb-2 clinochlore from the Achmatov mine, Ural Mountains, U.S.S.R., was investigated by neutron diffraction. The formula, based on electron microprobe and wet chemical analyses, is (Mg4.54Al0.97Fe2+ 0.28 Fe3+ 0.18Mn0.01)(Si2.85Al1.15)O10(OH)8. A refinement based on 512 unique reflections converged in space group C2/m to a final R =.066. Cation disorder was found in the two octahedral positions of the 2:1 layer, whereas partial Mg and Al ordering occurs in the interlayer sheet. The two hydroxyl dipoles are roughly perpendicular to the interlayer sheet, forming weak to medium hydrogen bonds with O…O distances of 2.859 and 2.881 Å. The OH-dipole of the 2:1 layer is perpendicular to the (001) plane.

Zusammenfassung

Zusammenfassung

Die Struktur eines monoklinen IIb-2 Klinochlors yon der Achmatov-Mine, Ural, UdSSR, wurde mit Neutronenbeugung untersucht. Mikrosondenanalyse und naßchemische Methoden ergaben die Zusammensetzung: (Mg4.54Al0.97Fe2+ 0.28Fe3+ 0.18Mn0.01)(Si2.85Al1.15)O10(OH)8. Die Verfeinerung mit 512 symmetrisch unabhängigen Reflexen konvergierte in Raumgruppe C2/m zu einem R = 0,066. Die Kationen der beiden oktaedrischen Positionen der 2:1-Schicht sind vollständig ungeordnet, während in der Zwischenschicht teilweise eine Ordnung von Mg und Al beobachtet wird. Die beiden Hydroxyl-Dipole stehen senkrecht auf der Zwischenschicht und bilden schwache bis mittelstarke Wasserstoffbrücken mit O…O-Abständen von 2,895 und 2,881 Å. Der OH-Dipol der 2:1-Schicht ist senkrecht zur 001-Fläche.

Keywords

Cation orderingChloriteCrystal structureHydrogen bondingNeutron diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 37 , Issue 6 , December 1989 , pp. 511 - 514
Copyright
Copyright © 1989, The Clay Minerals Society

References

Bailey, S. W. and Brown, B. E., 1962 Chlorite polytypism: I. Regular and semi-random one-layer structures Amer. Mineral. 47 819 – 850.Google Scholar
Bayliss, P., 1975 Nomenclature of the trioctahedral chlorites Canadian Mineral. 13 178 – 180.Google Scholar
Brown, B. E. and Bailey, S. W., 1963 Chlorite polytypism: II. Crystal structure of a one-layer Cr-chlorite Amer. Mineral. 48 42 – 61.Google Scholar
Joswig, W., 1972 Neutronenbeugungsmessungen an einem lAf-Phlogo-pit Neues Jahrb. Mineral. Monatsh. 1 – 11.Google Scholar
Joswig, W., Amthauer, G. and Takeuchi, Y., 1986 Neutron diffraction and Mössbauer spectroscopic study of clintonite (xanthophyllite) Amer. Mineral. 71 1194 – 1197.Google Scholar
Joswig, W. and Fuess, H. (1989) Refinement of a one-layer triclinic chlorite: Clays & Clay Minerals 37, (in press).CrossRefGoogle Scholar
Joswig, W., Fuess, H., Rothbauer, R., Takéuchi, Y. and Mason, S. A., 1980 A neutron diffraction study of a one-layer triclinic chlorite (penninite) Amer. Mineral. 65 349 – 352.Google Scholar
Koester, L. and Höhler, G., 1977 Neutron scattering lengths and fundamental neutron interactions Neutron Physics Berlin Springer 1 – 55.CrossRefGoogle Scholar
Renault, A., McIntyre, G. J., Collin, G., Pouget, J. P. and Comes, R., 1987 Structure of Ba2YCu3O6 26 J. Physique 48 1407 – 1412.CrossRefGoogle Scholar
Rule, A. C. and Bailey, S. W., 1987 Refinement of the crystal structure of a monoclinic ferroan clinochlore Clays & Clay Minerals 15 129 – 138.CrossRefGoogle Scholar
Steinfink, H., 1958 The crystal structure of chlorite I. A monoclinic polymorph Acta Crystallogr. 11 191 – 195.CrossRefGoogle Scholar
Stewart, J. M., Krüger, G. J., Ammon, H. L., Dickinson, L. and Hall, S. R., 1975 The XRAY System-Version of June 1972, updated Nov. 1975 College Park, Maryland Computer Science Center, University of Maryland.Google Scholar
Wilkinson, C. and Khamis, H. W. (1983) In Position-Sensitive Detection of Thermal Neutrons, Convert, P. and Forsyth, J. B., eds., Academic Press, New York, p. 358.Google Scholar
Zheng, H. and Bailey, S. W. (1989) The structures of inter-grown triclinic and monoclinic lib chlorites from Kenya. Clays & Clay Minerals 37, (in press).Google Scholar