In accord with the original interpretation of Liu et al. (J. Am. Chem. Soc. 1987, 109, 4282-4291), it has been demonstrated that electrochemical oxidation of the title compound in methylene chloride proceeds by a two-step process by which the square-pyramidal neutral reactant (SP) is oxidized to a cation of similar structure (SP+) followed by isomerization to the preferred trigonal-bipyramidal cation (TBP+). A combination of slow cyclic voltammetry near room temperature and fast scan experiments at low temperature has allowed determination of the thermodynamic and kinetic parameters for the conversion of SP+ to TBP+ (Delta H degrees = -6.05 kcal/mol; Delta S degrees = -3.97 cal mol(-1) K-1; Delta G degrees*(298) = 9.5 kcal/mol). The reversible formal potential for the SP/SP+ couple is +1.20 V vs cobaltocenium/cobaltocene in the same solvent and the reversible formal potential for the direct one-step oxidation of SP to TBP+ is 0.99 V, i.e., the direct oxidation requires 5 kcal/mol less energy than the two-step reaction. The fact that the reaction actually proceeds via the two-step pathway is explained by a large barrier to the direct oxidation, calculated to be greater than about 12 kcal/mol. It is argued that this large barrier is reasonable in view of the expected contribution from the outer and inner reorganization energies.