Crystal structure and phase transitions of Sr{sub 2}CdWO{sub 6}

Journal Article · Wed Aug 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.05.022· OSTI ID:21043800

Gateshki, M ^[1]; Faik, A ^[2]

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1. Australian Nuclear Science and Technology Organization, Private Mail Bag 1, Menai, NSW 2234 (Australia)
2. Fisika Aplikatua II Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, P.O. Box 644, Bilbao 48080 (Spain)

The crystal structure of Sr{sub 2}CdWO{sub 6}, prepared by solid state reaction, was determined by high-resolution X-ray diffraction at different temperatures. At room temperature, this compound has a monoclinic structure (space group P2{sub 1}/n) with a=5.7463(1), b=5.8189(1), c=8.1465(1), {beta}=90.071(1). At 1105 K the structure is converted to tetragonal (space group I4/m). Diffraction data also suggest that a cubic phase exists above 1220 K. Comparing the phase transition temperatures of Sr{sub 2}CdWO{sub 6} with those of other compounds of the Sr{sub 2}MWO{sub 6} family reported previously, it was observed that the transition temperatures are higher in compounds with low-tolerance factors. At the same time, the temperature range in which the intermediate tetragonal phase exists is reduced. -- The phase transition temperatures as a function of the tolerance factor t, calculated using bond lengths distances that give the nominal oxidation states of the cations in the bond-valence method. The phase transition temperatures increase at lower values of t. Also, the temperature range in which the tetragonal phase exists is narrower at low t. These results are very similar to those observed in Rb{sub 2}KBF{sub 2}(B=Sc,In,Lu,Er,Ho) elpasolites, and confirm that the most important factor governing the appearance of octahedral tilts in the double perovskite structure and the temperature range in which they exist is the mismatch between the size of the A cation and interstitial space between the BO{sub 6} and B{sup '}O{sub 6} octahedra.

• OSTI ID: 21043800
• Journal Information: Journal of Solid State Chemistry, Vol. 180, Issue 8; Other Information: DOI: 10.1016/j.jssc.2007.05.022; PII: S0022-4596(07)00213-7; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BOND LENGTHS
CADMIUM COMPOUNDS
INTERSTITIALS
MONOCLINIC LATTICES
OXIDES
PEROVSKITE
PHASE TRANSFORMATIONS
SPACE GROUPS
STRONTIUM COMPOUNDS
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 1000-4000 K
TETRAGONAL LATTICES
TRANSITION TEMPERATURE
TUNGSTEN COMPOUNDS
X-RAY DIFFRACTION