skip to main content

Title: Order-disorder in In{sup 3+} perovskites: The example of A(In{sub 2/3}B''{sub 1/3})O{sub 3} (A=Ba, Sr; B''=W, U)

We describe the preparation and structural characterization of four In-containing perovskites from neutron powder diffraction (NPD) and X-ray powder diffraction (XRPD) data. Sr{sub 3}In{sub 2}B''O{sub 9} and Ba(In{sub 2/3}B''{sub 1/3})O{sub 3} (B''=W, U) were synthesized by standard ceramic procedures. The crystal structure of the W-containing perovskites and Ba(In{sub 2/3}U{sub 1/3})O{sub 3} have been revisited based on our high-resolution NPD and XRPD data, while for the new U-containing perovskite Sr{sub 3}In{sub 2}UO{sub 9} the structural refinement was carried out from high-resolution XRPD data. At room temperature, the crystal structure for the two Sr phases is monoclinic, space group P2{sub 1}/n, where the In atoms occupy two different sites Sr{sub 2}[In]{sub 2d}[In{sub 1/3}B''{sub 2/3}]{sub 2c}O{sub 6}, with a=5.7548(2) A, b=5.7706(2) A, c=8.1432(3) A, {beta}=90.01(1){sup o} for B''=W and a=5.861(1) A, b=5.908(1) A, c=8.315(2) A, {beta}=89.98(1){sup o} for B''=U. The two phases with A=Ba should be described in a simple cubic perovskite unit cell (S.G. Pm3-bar m) with In and B'' distributed at random at the octahedral sites, with a=4.16111(1) A and 4.24941(1) A for W and U compounds, respectively. - Graphical abstract: The structure of the new uranium-based double perovskite Sr{sub 3}In{sub 2}UO{sub 9} is described and the true symmetry of themore » other title compounds are revisited. The presence of long-range ordering in the Sr samples, by contrast with the Ba perovskites, is related with the smaller unit cell and B-B distances in the Sr oxides, promoting the electrostatic repulsions between highly charged W{sup 6+} and U{sup 6+} cations as driving force for the long-range B-site ordering.« less
Authors:
 [1] ;  [2] ; ; ;  [3]
  1. Departamento de Quimica, Area de Quimica General e Inorganica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina), E-mail: salarreg@unsl.edu.ar
  2. Instituto de Ciencia de Materiales de Madrid, C.S.I.C., Cantoblanco, 28049 Madrid (Spain)
  3. Departamento de Quimica, Area de Quimica General e Inorganica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina)
Publication Date:
OSTI Identifier:
21212069
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 181; Journal Issue: 10; Other Information: DOI: 10.1016/j.jssc.2008.06.047; PII: S0022-4596(08)00344-7; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BARIUM COMPOUNDS; CERAMICS; CUBIC LATTICES; DISTANCE; INDIUM IONS; MONOCLINIC LATTICES; NEUTRON DIFFRACTION; OXIDES; PEROVSKITE; SPACE GROUPS; STRONTIUM COMPOUNDS; SYMMETRY; TUNGSTEN COMPOUNDS; TUNGSTEN IONS; URANIUM; URANIUM COMPOUNDS; URANIUM IONS; X-RAY DIFFRACTION