2003 Structure

200333.fm Page 15 Thursday, July 17, 2003 3:22 PM

StructureD 2000 Synthesis, Crystal Structure, and Solid State Phase Transition of Te4[AsF6]2·SO2.

— Dark red crystals of the title compound are prepared by oxidation of Te with AsF5 in liq. SO2 (77→298 K, several hours). Above 127 K Te4[AsF6]2·SO2 crystallizes in the orthorhombic space group Pnma with Z = 4. The structure contains square-planar rings, octahedra and SO2 molecules which bridge the edges of the Te4 squares. At 127 K Te4[AsF6]2·SO2 undergoes a phase transition to a monoclinic structure (space group P1121/a, Z = 4). The ions, which show rotational disorder in the room temp. modification, are ordered in the low temp. modification. The phase transition is accompanied by crystal twinning. — (BECK*, J.; STEDEN, F.; REICH, A.; FOELSING, H.; Z. Anorg. Allg. Chem. 629 (2003) 6, 1073-1079; Inst. Anorg. Chem., Rhein. Friedrich-Wilhelms-Univ., D-53121 Bonn, Germany; Ger., Abstr. Eng.) — Schramke

33- 015Te2+

4AsF-

6

AsF-6