Gibbs energy of formation of the Rh–Te intermetallic compounds Rh3Te2 and RhTe0.9

The vaporization behavior of the intermetallic compounds Rh3Te2 and RhTe0.9 was studied in the temperature range 1151–1234 and 1026–1092 K, respectively, by Knudsen effusion mass loss technique. The phase analysis of partially evaporated samples of Rh3Te2 (s) and RhTe0.9 (s) together with the available information on Te bearing vapor species revealed that the compounds incongruently volatilize as Rh3Te2 (s) = 3Rh (s) + 2/nTen (g) and 3RhTe0.9 (s) = Rh3Te2 (s) + 0.7/nTen (g), (n=1,2), respectively. The equilibrium vapor pressures of Te2 (g) and Te (g) were derived from the total pressure p(Ten) measured over the mixtures Rh3Te2 (s) and Rh (s), and RhTe0.9 (s) and Rh3Te2 (s) in the respective cases. The standard Gibbs energy of formation of Rh3Te2 and RhTe0.9 derived using the above vapor pressure data and other auxiliary data could be expressed by the equations ΔfG°(Rh3Te2, s) (kJ mol−1) = −176.9 + 0.039T±7.0 and ΔfG°(RhTe0.9, s) (kJ mol−1) = −74.7 + 0.015T±3.0 kJ mol−1, respectively.