Vibrational entropy of disordering in omphacite
- Author(s)
- Artur Benisek, Edgar Dachs, Michael A. Carpenter, Bastian Joachim-Mrosko, Noreen M. Vielreicher, Manfred Wildner
- Abstract
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(s)
- Department of Mineralogy and Crystallography
- External organisation(s)
- Paris-Lodron Universität Salzburg, University of Cambridge, Leopold-Franzens-Universität Innsbruck
- Journal
- Physics and Chemistry of Minerals
- Volume
- 50
- ISSN
- 0342-1791
- DOI
- https://doi.org/10.1007/s00269-023-01260-7
- Publication date
- 12-2023
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105116 Mineralogy, 105113 Crystallography
- Keywords
- ASJC Scopus subject areas
- General Materials Science, Geochemistry and Petrology
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/58fa41df-3943-4ce5-a471-5164ca846eef