Thermochemical properties of the gaseous molecules VO, VO2, and V2O4

Abstract

The gaseous molecules VO, VO2, and V2O4 were characterized thermochemically from the study of various all-gas equilibria carried out by means of the high temperature-mass spectrometry. The bond dissociation energies here determined for VO and VO2 are compared and discussed with previous results, while the molecule V2O4 was clearly identified for the first time. The thermochemical results obtained are: D°0(VO)=625.5±8.5 kJ mol−1, ΔH°f,298(VO,g)= 133.2±8.5 kJ mol−1; D°0(VO2)=1 177±18 kJ mol−1, ΔH°f,298(VO2,g)=−174±14 kJ mol−1; D°0,at(V2O4)=2880±23 kJ mol−1, ΔH°f,298(V2O4,g)=−878±23 kJ mol−1.