Standard enthalpies of formation of RhTi, RhZr and RhHf

Abstract

The standard enthalpies of formation of the intermetallic compounds RhTi, RhZr and RhHf have been determined by high temperature mixing calorimetry at 1400 K. The following values of ΔH f o are reported: RhTi, −143.0 ± 9.8 kJ mol −1; RhZr, −151.8 ± 7.1 kJ mol −1; RhHf, −191.6 ± 4.3 kJ mol −1. These results are compared with values predicted in the literature and with a recent experimental value for RhZr. Comparison of the new data with our recently published results for the corresponding compounds of palladium with titanium, zirconium and hafnium show that in both families there are increasing negative enthalpies of formation in the sequence TiX < ZrX < HfX.