Thermodynamic stability and impedance measurements of perovskite LuRhO3(s) in the Lu–Rh–O system

The Gibbs energy of formation of LuRhO3(s) has been determined using a solid-state electrochemical technique employing an oxide ion conducting electrolyte. The Gibbs energy of formation of LuRhO3(s) from elements in their standard state calculated from the data obtained can be represented by: {ΔfGo(LuRhO3, s)/(kJ mol−1) ± 1.35} = −1164.3 + 0.2685(T/K) (943 ≤ T/K ≤ 1121). The standard enthalpy of formation and entropy of the compound at 298.15 K has been derived following the second law method. The standard molar heat capacity of LuRhO3(s) was determined from 128 K to 846 K using a heat flux type differential scanning calorimeter. Based on the thermodynamic data for the compound, an oxygen potential diagram for the Lu–Rh–O system was computed. Impedance measurements on LuRhO3(s), suggests a semiconductor like behavior with low activation energy.