Measurements of Heat of Formation of GaP, InP, GaAs, InAs, GaSb and InSb

The heats of formation of six III-V compounds of GaP, InP, GaAs, InAs, GaSb and InSb were determined at 773 K from the heats of dissolution of these compounds and the components in a liquid tin solvent, using a Calvet-type twin solution calorimeter. The standard heats of formation at 298.15 K, ΔHf,298.15°, are: GaP (P: red) −103.2±1.7 kJ/mol, InP (P: red) −70.2±4.4 kJ/mol, GaAs −87.7±0.5 kJ/mol, InAs −60.0±1.0 kJ/mol, GaSb −45.9±0.3 kJ/mol and InSb −34.1±0.6 kJ/mol. A relation was found between the heats of formation and the bond formation energy, and the overlap interaction in the cohesive energies of these compounds. ΔHf,298.15° decreased linearly with increasing bond formation energy and overlap interaction energy per bond.