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A high‐pressure single‐crystal X‐ray diffraction study of V 3 O 5 including the phase transition at 6.2 GPa
Author(s) -
Åsbrink S.,
Malinowski M.
Publication year - 1987
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/s0021889887086837
Subject(s) - phase transition , valence (chemistry) , diamond anvil cell , diffraction , diffractometer , crystallography , bulk modulus , x ray crystallography , single crystal , phase (matter) , crystal structure , chemistry , crystal (programming language) , materials science , condensed matter physics , optics , physics , programming language , organic chemistry , computer science
The unit‐cell parameters of the mixed‐valence oxide V 3 O 5 have been studied as functions of pressure from 0.3 up to 7.5 GPa in a single‐crystal experiment involving measurements at 21 different pressure values. A diamond‐anvil high‐pressure (h.p.) cell of new construction [Malinowski (1987). Submitted to J. Appl. Cryst. ] mounted on a four‐circle X‐ray diffractometer was used. At P t = 6.25(9) GPa a phase transition was observed at room temperature. This is analogous to the semiconductor‐metal transition observed at T t = 428 K and normal pressure, which implies a change in the ordering of the metal‐atom valencies. The linear Eulerian strain tensor for the transition has been calculated. The bulk modulus K has been determined for the low‐pressure (l.p.) as well as for the h.p. phase: K l.p. (0.3–5.5 GPa) = 269(3), K h.p. (6.3–7.5 GPa) = 175(11) GPa. Certain anomalies in the cell‐parameter values in a small pressure interval around the phase transition indicate a preparation in the crystal structure for the transition in both the l.p. and the h.p. phase.