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Refinement of the Crystal Structure of Cronstedtite-3T

Published online by Cambridge University Press:  28 February 2024

Ľubomír Smrčok ,
Slavomil Ďurovič ,
Václav Petříček  and
Zdeněk Weiss
Ľubomír Smrčok
Affiliation:
Institute of Inorganic Chemistry, Slovak Academy of Sciences, 842 36, Bratislava, Czechoslovakia
Slavomil Ďurovič
Affiliation:
Institute of Inorganic Chemistry, Slovak Academy of Sciences, 842 36, Bratislava, Czechoslovakia
Václav Petříček
Affiliation:
Institute of Physics, Czechoslovak Academy of Sciences, 162 00, Prague, Czechoslovakia
Zdeněk Weiss
Affiliation:
Technical University of Mining and Metalurgy, 708 33 Ostrava-Poruba, Czechoslovakia
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Abstract

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The crystal structure of cronstedtite-3T from Kutná Hora (Bohemia, Czechoslovakia), space group P31, was refined to Rw(all) = 3.1% for 1336 independent diffractions. There are two and three independent tetrahedral and octahedral positions, respectively, in this structure. The tetrahedra are occupied by 0.75 Si and 0.25 Fe while the octahedra are uniformly occupied by Fe. The refinement process was hindered by two problems: a “strong” superposition structure (all atoms of the octahedral sheets, i.e., ÷ 70% of the total diffraction power contribute almost solely to the family diffractions with mod(h–k, 3) = 0), and a slight disorder of the investigated crystal. The first problem was resolved by a preliminary block-diagonal refinement procedure where the atoms coinciding in the superposition structure were separated into individual blocks. The second problem was resolved by including two scale factors into the final full-matrix refinement: one for family diffractions, the other for the remaining ones which are characteristic for this polytype.

Keywords

CronstedtiteOrder-disorder (OD)Polytypism
Type
Research Article
Information
Clays and Clay Minerals , Volume 42 , Issue 5 , October 1994 , pp. 544 - 551
Copyright
Copyright © 1994, Clay Minerals Society

References

Bailey, S. W., 1969. Polytypism of trioctahedral 1: 1 layer silicates. Clays & Clay Miner. 17: 355–371.CrossRefGoogle Scholar
Clegg, W., 1981. Faster data collection without loss of precision. An extension of the learnt profile method. Acta Crystallog. A37: 22–28.CrossRefGoogle Scholar
Cromer, D. T., and Mann, J. B.. 1968 . X-ray scattering factors computed from numerical Hartree-Fock wave functions. Acta Crystallog. A24: 321–324.CrossRefGoogle Scholar
Dornberger-Schiff, K., 1964. Grundzüge einer Theorie der OD-Strukturenaus Schichten. Abh. Dtsch. Akad. Wiss. Berlin, Kl.f.Chem. 3: 107 pp.Google Scholar
Dornberger-Schiff, K., and Durovic, S.. 1975a . OD interpretation of kaolinite-type structures—I: Symmetry of kaolinite packets and their stacking possibility. Clays & Clay Miner. 23: 219–229.CrossRefGoogle Scholar
Dornberger-Schiff, K., and Durovic, S.. 1975b . OD interpretation of kaolinite-type structures—II: The regular polytypes (MDO polytypes) and their derivation. Clays & Clay Miner. 23: 231–246.CrossRefGoogle Scholar
Ďurovič, S., 1979. Desymmetrization of OD structures. Kristall und Technik 14: 1047–1053.CrossRefGoogle Scholar
Ďurovič, S., 1981. OD-Charakter, Polytypie und Identifikation von Schichtsilikaten. Fortschr. Miner. 59: 191–226.Google Scholar
Durovic, S., 1992. Layer stacking in general polytypic structures. In International Tables for Crystallography, Vol. C. Wilson, A. J. C., ed. Dordrecht/Boston/London: Kluwer Academic Publications, 667–680.Google Scholar
Fichtner, K., 1977. Zur Symmetriebeschreibung von OD-Strukturen durch Brandtsche und Ehresmannsche Gruppoide. Beitr. z. Algebra und Geometrie 6: 71–99.Google Scholar
Franzini, M., 1969. The A and B mica layers and the crystal structure of sheet silicates. Contr. Min. Petrol. 21: 203–224.CrossRefGoogle Scholar
Geiger, C. A., Henry, D. L., Bailey, S. W., and Maj, J. J.. 1983 . Crystal structure of cronstedtite-2H 2. Clays & Clay Miner. 31: 97–108.CrossRefGoogle Scholar
Mikloš, D., 1975. Symmetry and polytypism of trioctahedral kaolin-type minerals: Ph.D. thesis. Institute of Inorganic Chemistry, Slovak Academy of Sciences, Bratislava (in Slovak).Google Scholar
Mikloš, D., and Durovic, S.. 1978 . Desymmetrization of trioctahedral kaolin-type minerals. Acta Crystallog. A34: S9.Google Scholar
Petříček, V., and Malý, V.. 1988 . The SDS system. Program package for X-ray structure determination. Institute of Physics, Czechoslovak Academy of Sciences.Google Scholar
Radoslovich, E. W., 1961. Surface symmetry and cell dimension of layer-lattice silicates. Nature 191: 67–68.CrossRefGoogle Scholar
Steadman, R., 1964. The structure of trioctahedral kaolin-type silicates. Acta Crystallog. 17: 924–927.CrossRefGoogle Scholar
Steadman, R., and Nuttall, P. M.. 1963 . Polymorphism in cronstedtite. Acta Crystallog. 16: 1–8.CrossRefGoogle Scholar
Steadman, R., and Nuttall, P. M.. 1964 . Further polymorphism in cronstedtite. Acta Crystallog. 17: 404–406.CrossRefGoogle Scholar
Templeton, D. H., and Templeton, L. K.. 1978 . AGNOST C. University of California at Berkeley, Berkeley.Google Scholar
Weiss, Z., Rieder, M., and Chmielová, M.. 1992 . Deformation of coordination polyhedra and their sheets in phyllosilicates. Eur. J. Mineral. 4: 665–682.CrossRefGoogle Scholar
Weiss, Z., Rieder, M., Chmielová, M., and Krajíček, J.. 1985 . Geometry of the octahedral coordination in micas: A review of refined structures. Amer. Mineral. 70: 747–757.Google Scholar
Zvyagin, B. B., 1967. Electron Diffraction Analysis of Clay Mineral Structures. New York: Plenum Press, 364 pp.CrossRefGoogle Scholar