Abstract
The equilibrium, B2O3(c, 1) + BF3(g) = (BOF)3(g), was studied in the temperature range of 330–1000°K by means of transpiration. The heat of reaction employing crystalline B2O3 was found to be 7.6 kcal/mole; while the liquid B2O3 yielded a ΔHr of 2.4 kcal/mole. These lead to a value of —567.8±0.5 kcal/mole for ΔHf298°K of (BOF)3(g) and a value of 88.7±2 cal/deg/mole for S298 of (BOF)3(g). Partial pressure studies employing mixtures of argon and BF3 indicated that dissociation of the trimer (BOF)3(g) is negligible in the temperature range investigated.