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High‐pressure properties of TiP 2 O 7 , ZrP 2 O 7 and ZrV 2 O 7
Author(s) -
Carlson Stefan,
Krogh Andersen Anne Marie
Publication year - 2001
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/s0021889800013856
Subject(s) - orthorhombic crystal system , tetragonal crystal system , materials science , crystallography , high pressure , supercell , diffraction , thermodynamics , crystal structure , chemistry , computer science , physics , optics , telecommunications , radar
High‐pressure synchrotron X‐ray powder diffraction studies of TiP 2 O 7 , ZrP 2 O 7 and ZrV 2 O 7 have been performed. The ZrV 2 O 7 structure undergoes a reversible transition at 1.38–1.58 GPa from cubic α‐ to pseudo‐tetragonal β‐ZrV 2 O 7 that displays an orthorhombic 2 × 3 × 3 supercell. At pressures above 4 GPa, ZrV 2 O 7 becomes irreversibly X‐ray amorphous. No such transformations are observed for TiP 2 O 7 and ZrP 2 O 7 , which compress smoothly up to the highest investigated pressures (40.3 and 20.5 GPa, respectively). These differences in high‐pressure properties are discussed in terms of the negative thermal expansion of ZrV 2 O 7 . The bulk moduli at ambient pressure ( B 0 ) for TiP 2 O 7 , ZrP 2 O 7 , α‐ZrV 2 O 7 and β‐ZrV 2 O 7 were estimated to be 42 (3), 39 (1), 17.0 (7) and 20.8 (10) GPa, respectively.