Valence Bond Formulations of Mechanisms for the Formation and Decomposition of N2O5

Abstract

Environmental Context. N2O5 is an important nitrogen reservoir in polar stratospheric clouds found in Antarctica and involved with the ozone hole. Here we provide valence bond representations for the gas-phase formation and decomposition of this molecule. Abstract. Qualitative valence bond considerations are used to suggest how electronic reorganization could proceed for (a) the formation of N2O5 via the reactions NO2 + O3 → NO3 + O2, and NO2 + NO3 → N2O5, and (b) the thermal decomposition of N2O5 via the following sets of reactions: (i) N2O5 → NO2 + NO3, 2NO3 → O2NOONO2 →2NO2 + O2; (ii) NO2 + NO3 → ONOONO2 → NO + O2 + NO2, NO + NO3 → 2NO2. Increased-valence structures, which possess one-electron bonds and fractional electron-pair bonds as well as ‘normal’ electron-pair bonds, are used to represent the electronic structures of the molecules.