Experimental and predicted stability of diatomic metals and metallic clusters

The experimental bond energies of atomic and polyatomic metals and intermetallic compounds are reviewed and discussed in terms of various empirical models of bonding, such as the Pauling model of a polar single bond, the valence bond approach for certain multiply bonded intermetallic molecules and the atomic cell model. Illustrations emphasize recent Knudsen effusion mass spectrometric results. For ligand-free diatomic metals a maximum dissociation energy of 640 ± 40 kJ mol–1 is predicted.