Orientational disorder in sodium cadmium trifluoride trihydrate, NaCdF{sub 3}.3H{sub 2}O
- Department of Chemistry, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE 68182 (United States)
- Department of Chemistry, University of Alberta, Edmonton, Alta., T6G 2G2 (Canada)
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States)
Attempts to synthesize the hypothetical anhydrous fluoroperovskite NaCdF{sub 3}, which has been predicted to be stable, resulted instead in a hydrated fluoride of nominal composition NaCdF{sub 3}.3H{sub 2}O. It decomposes to sodium fluoride, cadmium fluoride, and water at 60deg. C. Its structure has been determined by single-crystal X-ray diffraction. Na{sub 0.92(2)}Cd{sub 1.08}F{sub 3.08}.2.92H{sub 2}O crystallizes in the cubic space group Fm3-bar m with a=8.2369(4)A and Z=4. The structure is based on the NaSbF{sub 6}-type (an ordered variant of the ReO{sub 3}-type) and features tilted sodium- and cadmium-centred octahedra that are linked by shared vertices to form a three-dimensional network. Substitutional disorder occurs on the nonmetal site, which is occupied by both F and O atoms, and on one of the metal sites, which is occupied by 92% Na and 8% Cd. A four-fold orientational disorder of the tilted octahedra is manifested as partial occupancy (25%) of the nonmetal site. A scheme to synthesize the anhydrous fluoride is presented.
- OSTI ID:
- 20891652
- Journal Information:
- Materials Research Bulletin, Vol. 41, Issue 3; Other Information: DOI: 10.1016/j.materresbull.2005.07.015; PII: S0025-5408(05)00270-9; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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