The variation of lattice parameters with pressure was studied on single-crystals of Mo8O23 up to 6.03(7) GPa by X-ray diffraction methods. The crystal, which at ambient conditions has an incommensurately modulated phase with superspace group
B P2/c/11 (0.188,1/2,0.133)
is highly compressible, with a lock-in phase transition to a commensurate superstructure below 0.94(7) GPa and a reversible first-order phase transition between 1.40(7) and 1.77(7) GPa. The compressibility of the high-pressure phase results in an anisotropic crystal with lattice parameters alpha and beta only slightly changing with pressure contrary to the much more varying b and c. The high-pressure behaviour of both Mo8O23 phases can qualitatively be described by different rotations of the MoO6 octahedra leading to higher 0-0 coordination numbers and therewith to denser packings of oxygen atoms.
|Number of pages||8|
|Publication status||Published - 1994|
- HIGH PRESSURE
- PHASE TRANSITION