Thermodynamic functions and the enthalpies of formation of gaseous VOX3 vanadium oxotrihalides

Resumo

A critical analysis of experimental and theoretical data on the structure and vibrational frequencies of gaseous VOX₃ vanadium oxotrihalides is performed. The values of molecular constants are selected and the thermodynamic functions are calculated within a “rigid rotator–harmonic oscillator” approximation. Equations that approximate a temperature dependence of heat capacity within the temperature range of 298.15–3000 K are obtained. Analysis of the available experimental data allows the enthalpy of formation to be determined for gaseous VOCl₃ molecules. The enthalpies of formation for VOF₃, VOBr₃, and VOI₃ molecules are determined for the first time using this value and quantum-chemical calculations of energy of exchange reactions involving VOCl₃. The obtained results are added to the database of the IVTANTERMO software.