Heat capacity and T-p phase diagram of Cs2NH4GaF6 elpasolite
Résumé
Cs2NH4GaF6 prepared by solid-state reaction exhibits at room temperature a cubic FmView the MathML sourcem elpasolite structure with a0=9.167 Å. Calorimetric measurements have shown the presence of a first order phase transition at T0=161 K. Pressure dependence of the phase transition temperature has been studied by DTA under pressure. The data are analyzed in the framework of orientational disordering of [NH4]+ and [GaF6]3− ions.