The DFT calculated <S 2 > values, the energy difference between the BS and HS states, and the isotropic exchange parameters for Mn-Cr dimeric molecular fragments of 1. Evidently, there is considerable antiferromagnetic exchange between all Mn II -Cr III couples, ranging from -7 to -11 cm -1 values when J Ruiz is considered. As Mn II ion and Cr III ion have t2g 3 eg 2 and t2g 3 eg 0 electronic configurations, respectively, the metal-based magnetic orbitals based on three t2g orbitals of these ions facilitate significant orbital overlap through cyanide-bridging ligands resulting in dominant antiferromagnetic coupling .