Figure displays these magnetic centers in terms of selected natural orbitals and occupancies for the quintet, triplet, and singlet electronic states at three representative geometries for which those spin states are the ground electronic states according to our RAS-tPBE calculations. At high temperatures the magnetism arises due to the symmetric and antisymmetric linear combinations of the singly occupied dz 2 orbitals from one magnetic unit with zero orbital angular momentum about the Cr-Cr axis (L = 0) and the other magnetic unit is the orbital pair of dxy and dx 2 -y 2 orbitals, labeled in Figure as the L = 2 pair. As the temperature is reduced, the P5 ring of cation I expands, and the two Cr nuclei are brought closer together. Starting at around T = 150 K, this promotes the singlet-pairing of the two electrons in the L = 0 orbital pair, which gradually form a weak Cr-Cr covalent σ bonding interaction with a direct overlap of the dz 2 orbitals. This reduces the spin angular momentum of the predicted ground electronic state, from quintet to triplet. At 12 K (or < 25K), the incongruent symmetries of the L = 2 d orbitals and the pentagonal P5 unit preferentially stabilize one orbital pair (L = 2 pair) over the other, promoting another singlet pairing and finally reducing the total spin angular momentum of the ground electronic state to zero. This is supported by the fact that, the symmetry breaking of the P5 unit (P-P bond length becomes dissimilar at 12 K) brings the two Cr atoms closer to the phosphorus atoms, specifically toward two of the phosphorus atoms in 𝑋 12-I and 𝑋 12-II structures. The two spin-crossover steps for cation I, here at T ≈ 110 K and T < 25 K differ in character. The higher-temperature step, in which the electrons in the L = 0 pair transition between spin triplet and spin singlet, can be interpreted as an antiferromagnetic interaction between two Cr atoms: structural changes in the ligand promote the formation of a dz 2dz 2 covalent bond. The lower-temperature crossover, on the other hand, should be understood primarily in terms of a strong ligand-field effect splitting otherwise degenerate L = 2, d orbitals on both chromium atoms simultaneously. The effects of spin-orbit coupling likely play a significant role in the region 25K < T < 50K as the spin multiplets split due to zero-field splitting (see Table ). For cation II, a direct conversion to the S = 0 state occurs below 25 K, and hence a sharp spin transition takes place at the susceptibility curve.