Bonding in Dinuclear Metal Compounds

According to the magnitudes of the overlapping integrals as well as to the nodal planes that characterize these molecular orbitals, their energies are expected to be in the order 

The electron configuration associated to the formation of this quadruple bond is therefore 

With 8 electrons the electron configuration with maximal bond order is reached. Thus species with bond orders 3.5, 3,2.5, 2,1.5 or 1 may in principle be obtained by either reduction or oxidation of dimetallic compounds with quadruple bonds. 

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