Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide The effects of pressure on the crystal structure of scheelite-type perrhenates were studied using synchrotron powder X-ray diffraction and density-functional theory. At ambient conditions, the studied materials AgReO 4, KReO 4, and RbReO 4, exhibit a tetragonal scheelite-type crystal structure described by space group I 4 1 / a . Under compression, a transition from scheelite-to-M′-fergusonite (space group P 2 1 / c ) was observed at 1.6 and 7.4 GPa for RbReO 4 and KReO 4, respectively. The transition involves a relative volume decrease. On the other hand, AgReO 4 underwent a phase transition to the M-fergusonite structure (space group I 2/ a ) at 13.6 GPa. In this case there is no appreciable volume discontinuity. The room-temperature pressure–volume equation of state for the three studied perrhenates was estimated using a second-order Birch–Murnaghan equation of state. The results for the low-pressure phase are confirmed by density-functional theory calculations. The analysis of the bulk modulus shows that the compressibility of the compounds decreases following the sequence RbReO 4 > KReO 4 > AgReO 4, which is related to the compressibility of the RbO 8, KO 8, and AgO 8 bidisphenoid units. Density-functional theory also offers valuable insights into the elastic constants. Despite giving a good description for the low-pressure phase in the three compounds, density-functional theory cannot catch the structural phase transition observed in experiments. Reasons for it are discussed in the manuscript.
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: Ministerio de Ciencia, Innovación y Universidades, Elettra-Sincrotrone Trieste, European Commission, Generalitat Valenciana, University of Hyderabad, Horizon 2020 Framework Programme, HORIZON EUROPE Framework Programme, Horizon 2020, Agencia Estatal de Investigación, Conselleria d'Educació, Investigació, Cultura i Esport, NextGenerationEU
Awards: G1136303803, G1175115578, G120905174, G1272927172, G1422035950, G1530851820, G1647983775, G1689424966, G1980626683, G210041235, G2262748287, G2601397997, G280048558, G2896932043, G300979063, G3163709047, G34346518, G3480869486, G357246561, G3681454997, G4023678328, G4042783231, G425668148, G5080475149, G5195188938, G531036588, NEutrons and PHotons Elevating Worldwide Science (NEPHEWS), G6046390375, G6491918455, G6930660739, G698859354, G7084143925, G727093099, G792975244, G800561617, G8118709007, G8974392459, G96141678
OpenAlex ID: W4413533786