Measurement of the enthalpy of phase transition for iron chevrel phase sulphide in the temperature range from 300 to 500 K

Abstract

Enthalpy increment HT-H~9 K measurements have been made on iron Chevrel phase sulphide Fe2Mo6ST.8, in the temperature range 300 to 500 K by the drop method using a hightemperature Calvet-type twin calorimeter. The first-order phase transition of this sulphide from a triclinic (low-temperature phase) to a rhombohedral (high-temperature phase) occurred at 375 K, and the enthalpy was evaluated to be 6.0 kJ/mol. The heat capacities of iron Chevrel phase sulphide Fe2Mo6ST.8 were also calculated before and after the phase transition.