Low-Lying Electronic States and Dissociation Energies of the Monochlorides of Cr, Mn, Fe, Co, and Ni

Abstract

Published equilibrium data involving the gaseous monochlorides of Cr, Mn, Fe, Co, and Ni have been re-examined by thermochemical analysis, using more recent information on the low-lying electronic states, yielding D°₀ values in kcal mol^-1 of CrCl (90.0), MnCl (79.8), FeCl (79.3), CoCl (81.3), and NiCl (88.1). Although this revised approach is believed to yield more reliable values of the FeCl, CoCl, and NiCl dissociation energies, results show that use of M⁺ electronic levels in place of the adopted MCl values leads to alternate D°₀(MCl) values agreeing within 1.6 kcal mol^-1, providing a useful check on electronic-level contributions to the thermochemical calculations.