The large differences between the DFT and CASPT2 Cr-Cr bond distances are a direct result of multiconfigurational character. The occupation numbers (ONs) associated with the CASSCF active orbitals for the complexes with the longest and shortest Cr-Cr bonds, [Cr 2 (O 2 CCH 3 ) 4 ](H 2 O) 2 and Cr 2 (dmp) 4 , demonstrate this as they deviate significantly from 2.00, 1.00, or 0.00 (indicative of doubly, singly, or unoccupied orbitals, respectively) (Figures and). Moreover, the largest contribution to the CASSCF wavefunction for [Cr 2 (O 2 CCH 3 ) 4 ](H 2 O) 2 is the σ 2 π 4 δ 2 configuration with only a 6.4% weight (Table ). The σ 2 π 4 δ * 2 configuration follows with a contribution of 5.2%, while all other configurations contribute less than 4%. Furthermore, the effective bond order (EBO),