Gonzalez-Platas, J.; Rodriguez-Hernandez, P.; Muñoz, A.; Rodríguez-Mendoza, U.R.; Nénert, G.; Errandonea, D. A High-Pressure Investigation of the Synthetic Analogue of Chalcomenite, CuSeO3∙2H2O. Crystals2019, 9, 643.
Gonzalez-Platas, J.; Rodriguez-Hernandez, P.; Muñoz, A.; Rodríguez-Mendoza, U.R.; Nénert, G.; Errandonea, D. A High-Pressure Investigation of the Synthetic Analogue of Chalcomenite, CuSeO3∙2H2O. Crystals 2019, 9, 643.
Abstract
Synthetic chalcomenite-type cupric selenite CuSeO3∙2H2O has been studied at room temperature under compression up to pressures of 8 GPa by means of single-crystal X-ray diffraction, Raman spectroscopy, and density-functional theory. According to X-ray diffraction, the orthorhombic phase undergoes an isostructural phase transition at 4.0(5) GPa with the thermodynamic character being first-order. This conclusion is supported by Raman spectroscopy studies which have detected the phase transition at 4.5(2) GPa and by the first-principles computing simulations. The structure solution at different pressures has provided information on the change with pressure of unit-cell parameters as well as on the bond and polyhedral compressibility. A Birch-Murnaghan equation of state has been fitted to the unit-cell volume data. We found that chalcomenite is highly compressible with a bulk modulus of 42 – 49 GPa. The possible mechanism driving changes in the crystal structure is discussed, being the behavior of CuSeO3∙2H2O mainly dominated by the large compressibility of the coordination polyhedron of Cu. On top of that, an assignation of Raman modes is proposed based upon density-functional theory and the pressure dependence of Raman modes discussed. Finally, the pressure dependence of phonon frequencies is also reported.
Subject Areas
selenite; chalcomenite; crystal structure; x-ray diffraction; raman spectroscopy; high pressure; equation of state; density functional theory
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Javier Gonzalez-Platas
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