Effects of pressure on the local atomic structure of CaWO4 and YLiF4: Mechanism of the scheelite-to-wolframite and scheelite-to-fergusonite transitions
arXiv:cond-mat/0306193 · doi:10.1016/j.jssc.2003.10.017
Abstract
The pressure response of the scheelite phase of CaWO4 (YLiF4) and the occurrence of the pressure induced scheelite-to-wolframite (M-fergusonite) transition are reviewed and discussed. It is shown that the change of the axial parameters under compression is related with the different pressure dependence of the W-O (Li-F) and Ca-O (Y-F) interatomic bonds. Phase transition mechanisms for both compounds are proposed. Furthermore, a systematic study of the phase transition in 16 different scheelite ABX4 compounds indicates that the transition pressure increases as the packing ratio of the anionic BX4 units around the A cations increases.
38 pages, 10 figures (Figure 5 corrected), accepted for publication in Journal of Solid State Chemistry