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Phase transitions in ReO 3 studied by high‐pressure X‐ray diffraction
Author(s) -
Jørgensen J.E.,
Staun Olsen J.,
Gerward L.
Publication year - 2000
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889899016659
Subject(s) - monoclinic crystal system , diffraction , compressibility , phase (matter) , crystallography , x ray crystallography , trigonal crystal system , phase transition , powder diffraction , ion , materials science , high pressure , chemistry , x ray , ambient pressure , analytical chemistry (journal) , crystal structure , thermodynamics , optics , physics , organic chemistry , chromatography
ReO 3 has been studied at pressures up to 52 GPa by X‐ray powder diffraction. The previously observed cubic Im 3¯ high‐pressure phase was shown to transform to a monoclinic MnF 3 ‐related phase at about 3 GPa. All patterns recorded above 12 GPa could be indexed on rhombohedral cells. The compressibility was observed to decrease abruptly at 38 GPa. It is therefore proposed that the oxygen ions are hexagonally close packed above this pressure, giving rise to two rhombohedral phases labelled I and II. The zero‐pressure bulk moduli B o of the observed phases were determined and the rhombohedral phase II was found to have an extremely large value of 617 (10) GPa. It was found that ReO 3 transforms back to the Pm 3¯ m phase found at ambient pressure.