The nature of M–O bond in MOX4 compounds (M = Os, Ru; X = F, Cl, Br, I)

The nature of M–O bond in MOX4 compounds (where M = Ru or Os and X = F, Cl, Br or I) was analyzed by density functional theory methods at the BP86/LANL2DZ level of theory. The obtained charge density was analyzed by Fermi hole analysis, natural bond order (NBO) analysis and atoms-in-molecules (AIM)-based methods. The M–O bond is essentially a triple bond, although strongly polarized. The clearest differences in bonding between the Ru and Os compounds can be found in the M–O σ bonds, where in the Os compounds we find more charge density resting close to O.