Vibrational entropy of disordering in omphacite

Autor(en)
Artur Benisek, Edgar Dachs, Michael A. Carpenter, Bastian Joachim-Mrosko, Noreen M. Vielreicher, Manfred Wildner
Abstrakt

The cations of an ordered omphacite from the Tauern window were gradually disordered in piston cylinder experiments at temperatures between 850 and 1150 °C. The samples were examined by X-ray powder diffraction and then investigated using low-temperature calorimetry and IR spectroscopy. The low-temperature heat capacity data were used to obtain the vibrational entropies, and the line broadening of the IR spectra served as a tool to investigate the disordering enthalpy. These data were then used to calculate the configurational entropy as a function of temperature. The vibrational entropy does not change during the cation ordering phase transition from space group C2/c to P2/n at 865 °C but increases with a further temperature increase due to the reduction of short-range order.

Organisation(en)
Institut für Mineralogie und Kristallographie
Externe Organisation(en)
Paris-Lodron Universität Salzburg, University of Cambridge, Leopold-Franzens-Universität Innsbruck
Journal
Physics and Chemistry of Minerals
Band
50
ISSN
0342-1791
DOI
https://doi.org/10.1007/s00269-023-01260-7
Publikationsdatum
12-2023
Peer-reviewed
Ja
ÖFOS 2012
105116 Mineralogie, 105113 Kristallographie
Schlagwörter
ASJC Scopus Sachgebiete
Allgemeine Materialwissenschaften, Geochemistry and Petrology
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/58fa41df-3943-4ce5-a471-5164ca846eef