Crystal structures and transition mechanism of VO{sub 2}(A)
- Kyoto Univ. (Japan)
- Rigaku Corp., Akishima, Tokyo (Japan). X-ray Research Lab.
Structures of VO{sub 2}(A) have been redetermined by single-crystal diffractometry for low- (LTP) and high-temperature (HTP) phases at 298 and 473 K, respectively. The LTP adopts the tetragonal system P4/ncc with a = 8.4403(9) {angstrom}, c = 7.666(1) {angstrom}, and Z = 16, whereas the HTP adopts the body-centered tetragonal system I4/m with a = 8.476(2) {angstrom}, c = 3.824(2) {angstrom}, and Z = 8. The refinements led to R/R{sub w} = 0.031/0.032 for LTP and 0.012/0.033 for HTP. The structures of both phases consist of edge-sharing VO{sub 6} octahedra and exhibit quite similar oxygen frameworks. Through the transition the V{sup 4+}-V{sup 4+} bonding in LTP with a distance of 2.7695(8) {angstrom} is dissociated in HTP to a distance of 3.0794(3) {angstrom}. The transition occurs with cooperative movements of the V atoms, namely, a rotation around the c axis and a shift along the c axis. Strangely, twinning is induced on the LTP to HTP transition but disappears on the reverse transition.
- OSTI ID:
- 329162
- Journal Information:
- Journal of Solid State Chemistry, Vol. 141, Issue 2; Other Information: PBD: Dec 1998
- Country of Publication:
- United States
- Language:
- English
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