A quantitative study of hole-transfer superexchange in Class II mixed-valence complexes is presented. The free energy of resonance exchange was calculated from metal-metal. coupling elements derived from Hush and CNS models and compared to experimental values that were factored from the free energy of comproportionation. The Hush model gave acceptable results for only the most weakly coupled systems while the CNS model gave reasonable predictions throughout the range of coupling studied (valence trapped to nearly delocalized behavior).