Crystal structures and phase transitions of Sr{sub 2}CrSbO{sub 6}

Journal Article · Wed Jul 15 04:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.04.014· OSTI ID:21370474

Faik, A ^[1]; Gateshki, M ^[2]; Cuello, G J ^[1]

---

1. Fisika Aplikatua II Saila, Zientzia Fakultatea, Euskal Herriko Unibertsitatea, P.O. Box 644, Bilbao 48080 (Spain)
2. PANalytical, Lelyweg, Almelo 7600AA (Netherlands)

Sr{sub 2}CrSbO{sub 6} was synthesized by the conventional solid-state reaction process. X-ray powder diffraction (XRPD) and neutron powder diffraction (NPD) has been used to reinvestigate the structure at room temperature and to study the phase transitions at high- and low-temperature. Rietveld analysis revealed that Sr{sub 2}CrSbO{sub 6} crystallizes at room temperature in a monoclinic system having a space group I2/m, with a=5.5574(1) A; b=5.5782(1) A; c=7.8506(2) A and beta=90.06(2), no P2{sub 1}/n space group as was previously reported. The high-temperature study (300-870 K) has shown that the compound presents the following temperature induced phase-transition sequence: I2/m-I4/m-Fm-3m. The low-temperature study (100-300 K) demonstrated that the room-temperature I2/m monoclinic symmetry seems to be stable down to 100 K. - Graphical abstract: The components of the GM{sup 3+} mode, responsible for the breaking of the symmetry to the I4/mmm tetragonal space group from the Fm-3m, observed experimentally at high. This mode involves the movements of all the oxygen atoms in the octahedra: those located in the (00z) positions move to the center (or out of) of the octahedra, as shown in (a); and the oxygen atoms located in the xy plane move outwards (inwards) along the diagonals of the basal plane of the octahedra (b). As the octahedra are corner sharing if one octahedra stretches the other one expands. (c) On the other hand, the mode GM{sup 4+} is responsible for the breaking of the symmetry down to the I4/m space group, and involves movements only of the oxygen atoms located in the xy plane (c): those displacements can be viewed as rotations (tilts) of the octahedra around the tetragonal axis.

• OSTI ID: 21370474
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 7 Vol. 182; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALKALINE EARTH METAL COMPOUNDS
ANTIMONY COMPOUNDS
CHROMIUM COMPOUNDS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
MINERALS
MONOCLINIC LATTICES
MOTION
NEUTRON DIFFRACTION
OXIDE MINERALS
OXYGEN COMPOUNDS
PEROVSKITE
PEROVSKITES
PHASE TRANSFORMATIONS
ROTATION
SCATTERING
SOLIDS
SPACE GROUPS
STRONTIUM COMPOUNDS
SYMMETRY GROUPS
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TETRAGONAL LATTICES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION