title: Some comments on valence bond representations for the radical exchange reaction X*+R:Y-->X:R+Y*.
abstract: Qualitative valence bond formulations by Hiberty and co-workers (Hiberty, P. C.; Megret, C.; Song, L.; Wu, W.; Shaik, S. J. Am. Chem. Soc. 2006, 128, 2836) of mechanisms for the radical exchange reactions H*+F:H-->H:F+H* and F*+H:F-->F:H+F* are compared to a previously published formulation of the generalized radical exchange reaction X*+R:Y-->X:R+Y*. The former formulation uses covalent-ionic VB complexes, and the latter formulation, which is more general, involves the formation of reactant-like and product-like complexes at intermediate stages along the reaction coordinate.
authors.affiliation: School of Chemistry, The University of Melbourne, Victoria 3010, Australia. r.harcourt@unimelb.edu.au
authors.forename: Richard D
authors.initials: RD
authors.lastname: Harcourt
authors.forename: Karin
authors.initials: K
authors.lastname: Schaefer
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Coote