Phase transformations in ABO 4 type compounds under high pressure

Effects of pressure on the local atomic structure of CaWO4 and YLiF4: mechanism of the scheelite-to-wolframite and scheelite-to-fergusonite transitions

“…This behavior is reflected in Fig. 4, which shows that the c/a ratio in both compounds evolves in a different way under pressure, being c more compressible than a in CaWO 4 while the contrary is true for YLiF 4 In order to better understand the different anisotropic behavior of both scheelites under pressure, it is very useful to describe them in terms of the pressure response of the It is well known that application of pressure reduces the interatomic distances and the atomic sizes, being the large anions more compressible than the small cations [19,20]. Therefore, the effect of pressure is twofold:…”

Effects of pressure on PbWO4-III

“…For raspite (PbWO 4 -II), a thermal-driven raspite to scheelite-structured transition was identified at 538°C by an in situ transmission electron microscopy observation (Wang et al 2011). Monoclinic PbWO 4 -III (P2 1 /n, Z = 8) structure as a high-pressure polymorph has been proposed in a large number of scheelite-type tungstates and molybdates (Fukunaga and Yamaoka 1979;Errandonea and Manjon 2008). However, a detailed high-pressure study of the X-ray diffraction and Raman scattering of PbWO 4 -III is still lacking.…”

Experimental and Theoretical Study of Zircon and Scheelite Phases of DyVO4

“…A study performed for an example of GdVO 4 [15] shows that this phase may be nonstoichiometric, what leads to small but detectable lattice parameter changes of the order of 0.001 Å. The RVO 4 compounds are known to undergo a phase transition to a scheelite-type polymorph (space group I 1 /a) at pressures below 10 GPa [16,17] which remains metastable after releasing the pressure. For some of them, in particular for DyVO 4 , a mechanochemical way for the scheelite-type phase preparation has been documented [18].…”