Thermochemical data and phase transition of argyrodite-type ionic conductors ME6PS5HAL and ME7PS6 (ME = Cu, Ag; HAL = Cl, Br, I)
1985; Elsevier BV; Volume: 87; Linguagem: Inglês
10.1016/0040-6031(85)85351-x
ISSN1872-762X
AutoresSebastian Fiechter, E. Gmelin,
Tópico(s)Semiconductor materials and interfaces
ResumoThe molar heat capacities of five argyrodite compounds have been measured in the temperature range, 2–500 K by adiabatic and differential scanning calorimetry. The heat capacity of two other chalcogenides, Cu3PS4 and Ag3PS4, has been determined between 100 and 500 K. The Cu6PS5HAL (HAL = Cl, Br, I) compounds show structural phase transitions at 241, 257 and 270 K, respectively. In Cu6PS5Cl a second new phase transition has been detected at 165 K. These phase transformations have been characterized thermodynamically. The thermodynamic standard values of entropy, enthalpy and Gibbs free energy at 298.15 K were calculated from the specific heat data and the heat of formation was computed from the results of vapour pressure measurements and specific heat data.
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