Reaction Rates of Xenon Fluorides with Oxides of Nitrogen

Abstract

The rate of reaction of XeF₄ and XeF₂ with NO and with NO₂ has been studied between 300° and 350°K at pressures between 0.1 and 30 mm. The second‐order rate constant at 300°K and the activation energies are, respectively: XeF₄+NO, 3 liters/mole sec, 7 kcal/mole; XeF₂+NO, 0.3 liters/mole sec, 10 kcal/mole. The rate of NO₂ with XeF₄ and XeF₂ was too slow to observe, k2 reacts with NO or NO₂. By means of a Polanyi—Semenov plot, the reactions of XeF₄, XeF₂, and F₂ with oxides of nitrogen were combined to give an estimate of the successive dissociation energies of XeF₄, which are (kcal/mole): XeF₄→XeF₃+F, 48; XeF₃→XeF₂+F, 15; XeF₂→XeF+F, 54; XeF→Xe+F, 11. From these kinetic and thermochemical data a strong case can be made for the stepwise reduction of XeF₄.