CoSO₄·H₂O and its continuous transition compared to the compression properties of isostructural kieserite-type polymorphs

Autor(en)

Manfred Wildner, Martin Ende, Johannes M. Meusburger, Roland Kunit, Philipp Matzinger, Dominik Talla, Ronald Miletich

Abstrakt

The kieserite-type compound cobalt(II) sulfate monohydrate, CoSO4·H2O, has been investigated under isothermal (T = 295 K) hydrostatic compression up to 10.1 GPa in a diamond anvil cell by means of single-crystal X-ray diffraction and Raman spectroscopy. The monoclinic α-phase (space group C2/c) undergoes a second-order ferroelastic phase transition at Pc = 2.40(3) GPa to a triclinic β-phase (space group P11). Lattice elasticities derived from fitting third-order Birch-Murnaghan equations of state to the pressure dependent unit-cell volume data yield V0 = 354.20(6) Å3, K0 = 53.0(1.7) GPa, K′ = 5.7(1.8) for the α-phase and V0 = 355.9(8) Å3, K0 = 45.2(2.6) GPa, K′ = 6.6(6) for the β-phase. Crystal structure data of the high-pressure polymorph were determined at 2.98(6) and 4.88(6) GPa. The most obvious structural feature and thus a possible driving mechanism of the phase transition, is a partial rearrangement in the hydrogen bonding system. However, a comparative analysis of pressure-induced changes in the four kieserite-type compounds investigated to date suggests that the loss of the point symmetry 2 at the otherwise rather rigid SO4 tetrahedron, allowing symmetrically unrestricted tetrahedral rotations and edge tiltings in the β-phase, could be the actual driving mechanism of the phase transition.

Organisation(en)

Institut für Mineralogie und Kristallographie

Externe Organisation(en)

University of Exeter, Universität Wien

Journal

Zeitschrift fur Kristallographie - Crystalline Materials

Band

236

Seiten

225–237

Anzahl der Seiten

13

ISSN

2194-4946

DOI

https://doi.org/10.1515/zkri-2021-2038

Publikationsdatum

09-2021

Peer-reviewed

Ja

ÖFOS 2012

105116 Mineralogie, 105113 Kristallographie

Schlagwörter

ASJC Scopus Sachgebiete

Condensed Matter Physics, Allgemeine Materialwissenschaften, Inorganic Chemistry

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/c4c384fa-ca13-4bc3-a314-585218fd7a0e