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High‐pressure single‐crystal X‐ray diffraction studies of MoO 3 . I. Lattice parameters up to 7·4 GPa
Author(s) -
Åsbrink S.,
Kihlborg L.,
Malinowski M.
Publication year - 1988
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/s0021889888008271
Subject(s) - compressibility , diffraction , anisotropy , diffractometer , crystallography , lattice (music) , hydrostatic equilibrium , x ray crystallography , hydrostatic pressure , crystal structure , diamond anvil cell , single crystal , lattice constant , chemistry , materials science , condensed matter physics , thermodynamics , physics , optics , acoustics , quantum mechanics
The unit‐cell parameters of MoO 3 (space group Pbnm ) have been studied as functions of pressure from 0 to 7.41 GPa in a single‐crystal experiment involving measurements at 28 different pressure values. A diamond‐anvil high‐pressure cell mounted on a four‐circle X‐ray diffractometer was used. The compressibility of this layer structure was found to be very anisotropic. The mean linear compressibilities in the three main directions of the unit cell have the following values: a (0–7.41 GPa) = − 3.2 × 10 −3 (GPa) −1 , b (0–0.49 GPa) = − 3.5 × 10 −2 (GPa) −1 , b (1.54–7.41 GPa) = − 1.1 × 10 −2 (GPa) −1 , and c (0–7.41 GPa) = − 3.35 × 10 −3 (GPa) −1 , whered i is the length of a lattice vector d at the hydrostatic pressure P i . The compressibility in the [010] direction, i.e. normal to the layers, has a non‐linear region and is by far the largest one. On the other hand, the compressibility in the [001] direction, which is the direction of the chains of oxygen coordination polyhedra within each layer, is very small.