Heat of Formation and Entropy of (BOCl)3

Abstract

An experimental study of the equilibrium B₂O₃(l)+BCl₃(g) = (BOCl)₃(g) has been made by the method of transpiration in the temperature range of 536°—825°K. The enthalpy and entropy changes of the reaction in this temperature range were found to be 5.0±0.3 kcal/mole and 3.1±0.5 cal/deg/mole, respectively. The data have been interpreted to yield the heat of formation, ΔH°_f695°K = 391.5±0.3 kcal/mole, and entropy, S°_695°K = 124.2±0.5 cal/deg/mole, of gaseous (BOCl)₃. Partial pressure studies indicate that the quantity of the monomer, BOCl, present in the temperature range under consideration is negligible.