Published January 1996 | Version v1
Journal article

The fluorite-matrix-based Ba4R3F17 (R=Y,Yb) crystal structure. Ordering of cations and specific features of the anionic motif

  • 1. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskii pr. 59, Moscow, 117333 (Russian Federation)
  • 2. Institut d'Estudis Catalans University of Barcelona, Barcelona (Spain)
  • 3. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskii pr. 59, 117333 Moscow (Russian Federation)
  • 4. Bauman State Technological University, Moscow (Russian Federation)
  • 5. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskii pr. 59, Moscow, 117333 Moscow (Russian Federation)

Description

The crystal structures of two representatives of the family of ordered phases with the fluorite-based structure are determined from the x-ray diffraction data. The parameters obtained are a=b=11.075(1) and c=20.372(2) A for the Ba4Y3F17 structure and a=b=11.000(1) and c=20.262(1) A for the Ba4Yb3F17 structure, sp.gr. R3-bar. The structures are refined in the anisotropic approximation of atomic thermal vibrations up to Rw=0.0164 for Ba4Y3F17 and Rw=0.0159 for Ba4Yb3F17. It is shown that Ba and R cations in these structures are ordered and arranged by the motif of the cubic close packing characteristic of the fluorite-type structures. The reconstruction of coordination polyhedra (cubes) of the fluorite-type structure into monocapped square RF9 antiprisms, ten-vertex BaF10, and eleven-vertex BaF11 polyhedra is considered as well as the relation between these polyhedra in the structures

Additional details

Publishing Information

Journal Title
Crystallography Reports
Journal Volume
41
Journal Issue
1
Journal Page Range
p. 50-57
ISSN
1063-7745
CODEN
CYSTE3

Optional Information

Notes
Translated from Kristallografiya, ISSN 0023-4761, 41, 56-64 (January-February 1996); (c) 1996 MAIK/Interperiodika