Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-23T18:52:50.351Z Has data issue: false hasContentIssue false
  • English
  • Français

A study of possible extra-framework cation ordering in Pbca leucite structures with stoichiometry RbCsX2+Si5O12 (X = Mg, Ni, Cd)

Published online by Cambridge University Press:  08 February 2019

Anthony M. T. Bell Open the ORCID record for Anthony M. T. Bell [Opens in a new window]  and
C. Michael B. Henderson
Anthony M. T. Bell*
Affiliation:
Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, S1 1WB, UK
C. Michael B. Henderson
Affiliation:
School of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK
*
a)Author to whom correspondence should be addressed. Electronic mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Leucites are silicate framework structures with some of the silicon framework cations partially replaced by divalent or trivalent cations. A monovalent extraframework alkali metal cation is also incorporated to balance the charges. We have previously reported Pbca leucite structures with the stoichiometries Cs2X2+Si5O12 (X = Mg, Mn, Co, Ni, Cu, Zn, Cd) and Rb2X2+Si5O12 (X = Mg, Mn, Ni, Cd). These orthorhombic leucite structures have all the silicon and non-silicon framework cations completely ordered onto separate crystallographic sites. This structure has five distinct Si sites and 1 X site; there are also two distinct sites for the extra-framework Cs or Rb. We have recently synthesised leucite analogues with two different extra-framework cations, these have the stoichiometry RbCsX2+Si5O12 (X = Mg, Ni, Cd). The initial Rietveld refinements assumed 50% Cs and 50% Rb on each of the two extra-framework cation sites. The refined structures for X = Ni and Cd have (within error limits) complete extra-framework cation site disorder. However, for X = Mg there is partial ordering of the extra-framework cation sites, the site occupancies are:- Cs1 0.37(3), Rb1 0.63(3), Cs2 0.63(3), Rb2 0.37(3).

Keywords

X-ray powder diffractionRietveld refinementsilicate framework minerals
Type
Technical Articles
Information
Powder Diffraction , Volume 34 , Supplement S1 , September 2019 , pp. S2 - S7
Copyright
Copyright © International Centre for Diffraction Data 2019 

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

Bell, A. M. T., and Henderson, C. M. B. (1994a). “Rietveld refinement of dry-synthesized Rb2ZnSi5O12 leucite by synchrotron X-ray powder diffraction,” Acta Crystallogr. C50, 984–986.Google Scholar
Bell, A. M. T., and Henderson, C. M. B. (1994b). “Rietveld refinement of the structures of dry-synthesized M Fe(III) Si2O6 leucites (M = K,Rb,Cs) by synchrotron X-ray powder diffraction,” Acta Crystallogr. C50, 1531–1536.Google Scholar
Bell, A. M. T., and Henderson, C. M. B. (1996). “Rietveld refinement of the orthorhombic Pbca structures of Rb2CdSi5O12, Cs2MnSi5O12, Cs2CoSi5O12 and Cs2NiSi5O12 Leucites by Synchrotron X-ray powder diffraction,” Acta Crystallogr. C52, 2132–2139.Google Scholar
Bell, A. M. T., and Henderson, C. M. B. (2009). “Crystal structures and cation ordering in Cs2MgSi5O12, Rb2MgSi5O12 and Cs2ZnSi5O12 leucites,” Acta Crystallogr. B65, 435–444.Google Scholar
Bell, A. M. T., and Henderson, C. M. B. (2012). “High-temperature synchrotron X-ray powder diffraction study of Cs2XSi5O12 (X = Cd, Cu, Zn) leucites,” Mineral. Mag. 76(5), 1257–1280.Google Scholar
Bell, A. M. T., and Henderson, C. M. B. (2016). “Rietveld refinement of the crystal structures of Rb2XSi5O12 (X = Ni, Mn),” Acta Crystallogr. E72, 249–252.Google Scholar
Bell, A. M. T., and Henderson, C. M. B. (2018). “Crystal structures of K2[XSi5O12] (X = Fe2+, Co, Zn) and Rb2[XSi5O12] (X = Mn) leucites: comparison of monoclinic P21/c and Ia $\bar{3}$d polymorph structures and inverse relationship between tetrahedral cation (T = Si and X)—O bond distances and intertetrahedral T—o—T angles,” Acta Crystallogr. B74, 274–286.Google Scholar
Bell, A. M. T., Henderson, C. M. B., Redfern, S. A. T., Cernik, R. J., Champness, P. E., Fitch, A. N., and Kohn, S. C. (1994a). “Structures of synthetic K2MgSi5O12 leucites by integrated X-ray powder diffraction, electron diffraction and 29Si MAS NMR methods,” Acta Crystallogr. B50, 31–41.Google Scholar
Bell, A. M. T., Redfern, S. A. T., Henderson, C. M. B., and Kohn, S. C. (1994b). “Structural relations and tetrahedral ordering pattern of synthetic orthorhombic Cs2CdSi5O12 leucite: a combined synchrotron X-ray powder diffraction and multinuclear MAS NMR study,” Acta Crystallogr. B50, 560–566.Google Scholar
Bell, A. M. T., Knight, K. S., Henderson, C. M. B., and Fitch, A. N. (2010). “Revision of the structure of Cs2CuSi5O12 leucite as orthorhombic Pbca,” Acta Crystallogr. B66, 51–59.Google Scholar
Finger, L. W., Cox, D. E., and Jephcoat, A. P. (1994). “A correction for powder diffraction peak asymmetry due to axial divergence,” J. Appl. Crystallogr. 27, 892–900.Google Scholar
Gatta, G. D., Rotiroti, N., Fisch, M., Kadiyski, M., and Armbruster, T. (2008). “Stability at high-pressure, elastic behaviour and pressure-induced structural evolution of CsAlSi5O12, a potential host for nuclear waste,” Phys. Chem. Minerals 35, 521–533.Google Scholar
Momma, K., and Izumi, F. (2011). “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr. 44, 1272–1276.Google Scholar
PANalytical (2009). High Score Plus 2.2e (Computer Software). PANalytical, Almelo, The Netherlands.Google Scholar
Redfern, S. A. T., and Henderson, C. M. B. (1996). “Monoclinic-orthorhombic phase transition in the K2MgSi5O12 leucite analog,” Am. Mineral. 81, 369–374.Google Scholar
Rietveld, H. M. (1969). “A profile refinement method for nuclear and magnetic structures,” J. Appl. Crystallogr. 2, 65–71.Google Scholar
Robinson, K., Gibbs, G. V., and Ribbe, P. H. (1971). “Quadratic elongation: a quantitative measure of distortion in coordination polyhedra,” Science 172, 567–570.Google Scholar
Rodríguez-Carvajal, J. (1993). “Recent advances in magnetic structure determination by neutron powder diffraction,” Physica B 192, 55–69.Google Scholar
van Laar, B., and Yelon, W. B. (1984). “The peak in neutron powder diffraction,” J. Appl. Crystallogr. 17, 47–54.Google Scholar
Supplementary material: File

Bell and Henderson supplementary material

Bell and Henderson supplementary material 1

Download Bell and Henderson supplementary material(File)
File 384.8 KB