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Refinement of the Crystal Structure of Phengite-2M1

Published online by Cambridge University Press:  02 April 2024

Audrey C. Rule  and
S. W. Bailey
Audrey C. Rule
Affiliation:
Department of Geology and Geophysics, University of Wisconsin-Madison, Madison, Wisconsin 53706
S. W. Bailey
Affiliation:
Department of Geology and Geophysics, University of Wisconsin-Madison, Madison, Wisconsin 53706
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Abstract

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The crystal structure of phengite-2M1 from Rio de Oro, Spanish Sahara, was refined in space group C2/c to a residual of 3.3% with 1267 independent X-ray diffraction reflections. The composition of the mica determined by electron microprobe analysis is (K0.948Na0.051Ba0.027)(Al1.510Mg0.273Fe0.144Cr0.095Ti0.010Mn0.003)2.035(Si3.253Al0.747)O10(OH)2. The cell dimensions are a = 5.2153(5), b = 9.043(2), c = 19.974(9) Å, β = 95.789(9)°, and V = 937.2(3) Å3. The substitution of Si for Al in the tetrahedral sheet and larger divalent cations for Al in the octahedra allows the amount of distortions that are generally required to alleviate tetrahedral-octahedral sheet lateral misfit in muscovite, such as tetrahedral rotation and octahedral flattening, to be reduced. The O…H vector is nearly horizontal and points slightly into the octahedral sheet where it may be involved in hydrogen bond contacts inside M(1). In contrast to previously reported refinements of all but one other phengite, no ordering of tetrahedral cations was found in the study specimen. This disorder is considered to be due to the low-pressure, high-temperature amphibolite facies environment of crystallization.

Keywords

Cation orderingCrystal structureMicaPhengite
Type
Research Article
Information
Clays and Clay Minerals , Volume 33 , Issue 5 , October 1985 , pp. 403 - 409
Copyright
Copyright © 1985, The Clay Minerals Society

References

Arribas, A., 1968 El Precámbrico del Sahara español y sus relaciones con las series sedimentarias más modernas Boletín Geológico y Minero. T. 79–5 445–480.Google Scholar
Bailey, S. W., 1984 Review of cation ordering in micas Clays & Clay Minerals 32 81–92.CrossRefGoogle Scholar
Bookin, A. S. and Drits, V. A., 1982 Factors affecting orientation of OH-vectors in micas Clays & Clay Minerals 30 415–421.CrossRefGoogle Scholar
Bookin, A. S., Drits, V. A., Rozdestvenskaya, I. V., Semenova, T. F. and Tsipursky, S. I., 1982 Comparison of orientations of OH-bonds in layer silicates by diffraction methods and electrostatic calculations Clays & Clay Minerals 30 409–414.CrossRefGoogle Scholar
Busing, W. R., Martin, K.O., and Levy, H. A. (1962) ORFLS, a Fortran crystallographic least-squares refinement program: Oak Ridge National Laboratory, Oak Ridge, Tennessee, ORNL-TM-305.CrossRefGoogle Scholar
Busing, W. R., Martin, K. O., and Levy, H. A. (1964) ORFFE, a Fortran crystallographic function and error program: Oak Ridge National Laboratory, Oak Ridge, Tennessee, ORNL-TM-306.CrossRefGoogle Scholar
Cromer, D. T. and Mann, J. B., 1968 X-ray scattering factors computed from numerical Hartree-Fock wave functions Acta Crystallogr. A24 321–324.CrossRefGoogle Scholar
Giese, R. F. Jr., 1979 Hydroxyl orientations in 2:1 phyllosilicates Clays & Clay Minerals 27 213–223.CrossRefGoogle Scholar
Güven, N., 1971 The crystal structure of 2M 1 phengite and 2M 1 muscovite Z. Kristallogr. 134 196–212.Google Scholar
Güven, N. and Burnham, C. W., 1967 The crystal structure of 3T muscovite Z. Kristallogr. 125 1–6.CrossRefGoogle Scholar
North, A. C. T., Phillips, D. C. and Mathews, F., 1968 A semi-empirical method of absorption correction Acta Crystallogr. A24 351–359.CrossRefGoogle Scholar
Rothbauer, R., 1971 Untersuchung eines 2M 1-Muskovits mit Neutronenstrahlen N. Jahrb. Mineral. Monatsh. 143–154.Google Scholar
Sidorenko, O. V., Zvyagin, B. B. and Soboleva, S. V., 1975 Crystal structure refinement for 1M dioctahedral mica Soviet Phys. Crystallogr. 20 332–335.Google Scholar
Tsipursky, S. I., 1979 The refinement of the crystal structure of celadonite by electron diffraction oblique texture method with electronometric measurements of intensity Proc. VIII Conf. X-ray Study of Mineral Raw Materials, Moscow, 1979 61.Google Scholar
Tsipursky, S. I. and Drits, V. A., 1977 Effectivity of the electronic method of intensity measurement in structural investigation by electron diffraction Izv. Akad. Nauk S.S.S.R., Ser. Phys. 41 2263–2271.Google Scholar
Zhoukhlistov, A. P., Zvyagin, B. B. and Shuriga, T. N., 1983 Electron diffraction investigation of the crystal structure of di-trioctahedral Li,Fe-phengite 1M Soviet Phys. Crystallogr. 28 518–521.Google Scholar
Zhoukhlistov, A. P., Zvyagin, B. B., Soboleva, S. V. and Fedotov, A. F., 1973 The crystal structure of the dioctahedral mica 2M 1 determined by high voltage electron diffraction Clays & Clay Minerals 21 465–470.CrossRefGoogle Scholar