Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-08T00:19:50.508Z Has data issue: false hasContentIssue false
  • English
  • Français

A structural model for charoite

Published online by Cambridge University Press:  05 July 2018

I. V. Rozhdestvenskaya ,
T. Kogure ,
E. Abe  and
V. A. Drits
I. V. Rozhdestvenskaya*
Affiliation:
Department of Crystallography, Geological Faculty, Saint Petersburg State University, University emb. 7/9, St Petersburg 199034, Russia
T. Kogure
Affiliation:
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
E. Abe
Affiliation:
Department of Materials Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
V. A. Drits
Affiliation:
Geological Institute RAN, Pyzhevsky Lane 7, Moscow 119017, Russia
*
* E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

The crystal structure of charoite was investigated mainly by using selected-area electron diffraction (SAED), X-ray diffraction (XRD) and high-resolution electron microscopy (HREM). SAED and XRD patterns indicate that the structure has a monoclinic cell: a = 32.296, b = 19.651, c = 7.16 Å, β = 96.3° and V = 4517 Å3. The space group inferred from systematic absences and HREM images is P21/m. A model of the charoite structure is proposed that is based on the features of related Ca-alkaline silicate structures and HREM images. The structure of charoite consists of three different silicon-oxygen radicals (polymerized SiO4 tetrahedra) which are located between Ca polyhedra. Two of these radicals form continuous tubular structures comprising pectolite-like tetrahedral chains. Calcium polyhedra are joined to form blocks, each of which consists of four columns sharing edges and apices. Potassium and H2O molecules are probably located inside the tubular silicate radicals. From these results, a general formula is derived: K6-7(Ca,Na)18[(Si6O17)(Si12O30)(Si18O45)](OH,F)2.nH2O with two formula units in the unit cell (Z = 2).

Keywords

charoitecrystal structurehigh-resolution electron microscopy.
Type
Research Article
Information
Mineralogical Magazine , Volume 73 , Issue 5 , October 2009 , pp. 883 - 890
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2009

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

Abe, E., Yan, Y. and Pennycook, S.J. (2004) Quasicrystals as cluster aggregates. Nature Materials, 3, 759—767.CrossRefGoogle ScholarPubMed
Chiragov, M.I. and Shirinova, A.F. (2004) Crystal structure of charoite; relations to structures of miserite, canasite and okenite. Mineralogicheskiy Zhurnal, 26(4), 5—9. (in Russian).Google Scholar
Kilaas, R. (1998) Optimal and near-optimal filters in high-resolution electron microscopy. Journal of Microscopy, 190, 45—51.CrossRefGoogle Scholar
Kogure, T., Eilers, P.H. and Ishizuka, K. (2008) Application of optimum HRTEM noise filters in mineralogy and related sciences, Microscopy and Analysis, 22, S11—S14.Google Scholar
Konev, A.A., Vorob’ev, E.I. and Lazebnik, K.A. (1996) Mineralogy of Murunskii Alkaline Massif. Nauchno- Izdatelsky Tsentr Ob’edinennogo Instituta Geologii, Geofiziki, Mineralogii, Siberian Brench of Russian Akademy of Science, Novosibirsk, Russia, 221 pp.Google Scholar
Marks, L.D. (1996) Wiener-filter enhancement of noisy HREM images. Ultramicroscopy, 62, 43—52.CrossRefGoogle ScholarPubMed
Merlino, S. (1983) Okenite, Ca10Si18O46-18(H2O): the first example of a chain and sheet silicate. American Mineralogist, 68, 614—622.Google Scholar
Nikishova, L.V., Lazebnik, K.A. and Lazebnik, Yu.D. (1985) About crystallochemical formulae of charoite. Pp. 100—105 in: Crystal Chemistry and Structure of Minerals. Nauka, Leningrad, Russia.Google Scholar
Rogova, V.P., Rogov, Yu.G., Drits, V.A. and Kuznetsova, N.N. (1978) Charoite - a new mineral and a new jewelry stone. Zapiski Vsesojuznogo Mineralogicheskogo Obshchestva, 107, 94—100.(in Russian).Google Scholar
Rozhdestvenskaya, I.V. and Nikishova, L.V. (2002) Characteristics of Alkali Calcium Silicates from Charoitites. Crystallography Reports. 47(4), 545—554.CrossRefGoogle Scholar
Vorob’ev, E.I. (2008) Charoite (L.D. Zorina, editor). Academy Publishing ‘Geo’, Novosibirsk, Russia, 140 pp.Google Scholar