Hostname: page-component-76fb5796d-vfjqv Total loading time: 0 Render date: 2024-04-29T15:47:49.525Z Has data issue: false hasContentIssue false
  • English
  • Français

Structures of Brittle Micas

Published online by Cambridge University Press:  01 January 2024

Y. Takéuchi
Y. Takéuchi*
Affiliation:
Mineralogical Institute, University of Tokyo, Japan
Get access Rights & Permissions [Opens in a new window]

Abstract

The crystal structures of xanthophyllite, CaMg2Al(Al3Si)O10(OH)2(a 1M structure) and margarite CaAl2(Al2Si2)O10(OH)2(a 2M1 structure), have been refined by three-dimensional least squares. Ordering of Mg and Al has been observed in the octahedral layers of xanthophyllite. There is no significant evidence for ordering among cations in the silicate layers of margarite. The tetrahedra are rotated about 23° in xanthophyllite and about 21° in margarite. The configuration of the octahedral layers in margarite has the same features as those in muscovite and dickite.

The mode of deformation of the silicate layer is roughly similar in both structures, but there are important differences. These differences are caused by the different configurations of the octahedral layers and are a common feature among micas. In the aluminum octahedral layer, the oxygen hexagons whose corners are apices of tetrahedra have short edges of 2.81Å and a pair of longer edges of 3.35Å (distances are averages obtained from the structures of margarite, muscovite and dickite). Because of these longer edges, the tetrahedra in the dioctahedral micas are tilted in addition to having rotations caused by the short edges. The z-parameters of the basal oxygen atoms in the tetrahedra thus show maximum deviations of 0.19 ± 0.03Å in margarite and 0.12 ± 0.03Å for muscovite. On the other hand, in trioctahedral micas, the edges of the oxygen hexagons are almost the same length, with a maximum deviation of 0. 05Å. The silicate layers in trioctahedral micas are accordingly almost free from tilting of tetrahedra. The difference in z-parameters in dioctahedral micas causes a corrugation of layers and also causes a shift of interlayer cations.

It is known that in trioctahedral micas, the direction of the OH bond is perpendicular to (001), while in muscovite it is inclined to the b-axis. Taking into account this asymmetrical orientation of the OH bond, together with the above-mentioned interlayer cation shifts, it is possible to show that a layer stacking by the operation of the twofold axis in the space group of the 2M1 structure is no longer identical with that produced by rotations of ± 120° about an axis perpendicular to (001). A more restricted number of operations would therefore be possible in the generation of polytypes.

An index, D, has been defined that is a direct measure of the misfit between octahedral and tetrahedral layers. It will be shown that the layer silicates may be classified into three categories with the aid of this index.

Type
Symposium on Structural Aspects of Layer Silicate
Information
Clays and Clay Minerals (National Conference on Clays and Clay Minerals) , Volume 13 , February 1964 , pp. 1 - 25
Copyright
Copyright © The Clay Minerals Society 1964

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

Axelrod, J. M., and Grimaldi, F. S. (1949) Muscovite with small optic axial angle, Am. Mineralogist 34, 559–72.Google Scholar
Bates, T.F., Hildebrand, F. A., and Swineford, A. (1950) Morphology and structure of endellite and halloysite, Am. Mineralogist 35, 467–84.Google Scholar
Bates, T. F. (1959) Morphology and crystal chemistry of 1: 1 layer lattice silicates, Am. Mineralogist 44, 78–114.Google Scholar
Belov, N. V. (1963) Crystal Chemistry of Large-Cation Silicates, Consultant Bureau, New York.Google Scholar
Bradley, W. F. (1940) Structure of attapulgite, Am. Mineralogist 25, 405–10.Google Scholar
Bradley, W. F. (1959) Current progress in silicate structures, Clays and Clay Minerals, 6th Conf. [1957], pp. 18–25, Pergamon Press, New York.Google Scholar
Bragg, W. L. (1937) Atomic Structure of Minerals, Cornell University Press, Ithaca, New York.Google Scholar
Brown, B. E., and Bailey, S. W. (1963) Chlorite polytypism, II, Crystal structure of a one-layer Cr-chlorite, Am. Mineralogist 48, 42–61.Google Scholar
Caillère, S., and Hénin, S. (1961) Palygorskite, X-ray Identification and Crystal Structures of Clay Minerals, (Edited by Brown, T.), pp. 343–53, Mineralogical Society, London.Google Scholar
Chalmers, R. A., Dent, L. S., and Taylor, H. F. W. (1958) Zeophyllite, Mineral. Mag. 31, 726–35.Google Scholar
Deer, W. A., Howie, R. A., and Zussman, J. (1962) Rock-Forming Minerals, Vol. 3, (Sheet Silicates), Longmans, London.Google Scholar
Forman, S. A. (1951) Xanthophyllite, Am. Mineralogist 36, 450–7.Google Scholar
Koch, G. (1935) Chemische und physikalisch-optische Zusammenhänge innerhalb der Sprödglimmergruppe, Chem. Erde 9, 453–63.Google Scholar
Kunze, G. (1956) Die gewellte Struktur des Antigorites, I, Z. Krist. 108, 82–107.CrossRefGoogle Scholar
Kunze, G. (1958) Die gewellte Struktur des Antigorites, II, Z. Krist. 110, 282–320.CrossRefGoogle Scholar
Mathieson, A. McL. (1958) Mg-vermiculite, a refinement and re-examination of crystal structure of the 14.36A phase, Am. Mineralogist 43, 216–27.Google Scholar
Megaw, Helen D. (1934) The crystal structure of hydragillite, Al(OH)3, Z. Krist. 87, 185–204.Google Scholar
Morimoto, N., Donnay, G., Takeda, H., and Donnay, J. D. H. (1963) Crystal structure of synthetic iron mica, Acta Cryst. 16, A 14.Google Scholar
Newnham, R. E. (1961) A refinement of dickite structure and some remarks on polytypism in kaoline minerals, Mineral. Mag. 32, 683–704.Google Scholar
Niggli, E. (1955) Zum Vorkommen von Kalkglimmern (Margarit, Clintonit) in der Schweizer Alpen, Leidse Geol. Mededel 20, 165–70.Google Scholar
Preisinger, A. (1959) X-ray study of the structure of sepiolite, Clays and Clay Minerals, 6th Conf. [1957], pp. 61–7, Pergamon Press, New York.Google Scholar
Radloslovich, E. W. (1959) Structural control of polymorphism in micas, Nature 183, 253.CrossRefGoogle Scholar
Radoslovich, E. W. (1960) The structure of muscovite, KAl2 (Si3Al)O10(OH)2, Acta Cryst 13, 919–32.CrossRefGoogle Scholar
Radoslovich, E. W., and Norrish, K. (1962) The cell dimensions and symmetry of layer-lattice silicates I. Some structural considerations. Am. Mineralogist 47, 599–616.Google Scholar
Sadanaga, R., and Takéuchi, Y. (1961) Polysynthetic twinning of micas, Z. Krist. 116, 406–29.CrossRefGoogle Scholar
Sanero, E. (1940) La struttura della xantofillite, Periodico Mineral. (Rome) 11, pp. 53–77.Google Scholar
Serkatosa, J. M., and Bradley, W. F. (1958) Infra-red absorption of OH bonds in micas, Nature 181, 111.CrossRefGoogle Scholar
Smith, J. V., and Bailey, S. W. (1963) Second review of Al—O and Si—O tetrahedral distances. Acta Cryst 16, 801–11.CrossRefGoogle Scholar
Steinfink, H., and Brunton, G. (1956) The crystal structure of amesite, Acta Cryst. 9, 487–92.CrossRefGoogle Scholar
Steinfink, H. (1962) Crystal structure of a trioctahedral mica, phlogopite, Am. Mineralogist 47, 886–96.Google Scholar
Takeuchi, Y. (1958) A detailed investigation of the structure of hexagonal BaAl2Si2O3 with reference to its α-β inversion, Mineral. J. 2, 311–32.Google Scholar
Takéuchi, Y., and Donnay, G. (1959) The crystal structure of hexagonal CaAl2Si2O3 Acta Cryst 12, 465–70.CrossRefGoogle Scholar
Takuéchi, Y., and Sadanaga, R. (1959) The crystal structure of xanthophyllite, Acta Cryst 12, 945–6.Google Scholar
Takuéchi, Y., Kawada, L, and Sadanaga, R. (1963) The crystal structure and poly- types of manganpyrosmalite, Acta Cryst. 16, A 16.Google Scholar
Tsuboi, M. (1950) On the positions of the hydrogen atoms in the crystal structure of muscovite, as revealed by the infra-red absorption study, Bult Chem. Soc. Japan 23, 83–8.Google Scholar
Vedder, W., and McDonald, R. S, (1963) Vibrations of the OH ions in muscovite, J. Chem. Phys. 38, 1583–90.CrossRefGoogle Scholar
Yoder, H. S. Jr., and Eugster, H. P. (1955) Synthetic and natural muscovite, Geochim. Cosmochim. Acta, 8, 225–80.CrossRefGoogle Scholar
Woodrow, P. J. (1963) The crystal structure of astrophyllite, Acta Cryst. 16, A 16–17.Google Scholar
Zvyagin, B. B. (1960) Electron-diffraction determination of the structure of kaolinite, Soviet Phys.—Cryst, 2, 388–94.Google Scholar
Zvyagin, V. V., and Mishchenko, K. S. (1963) Electronographic data on the structure of phlogopite-biotite, Soviet Phys.—Cryst. 7, 502–5.Google Scholar