Band structures and electronic properties of MC2 were studied by density functional theory (DFT) calculation. The chemical bonds are admixed with an ionic bond between M2+ and C-2(2-) and a strong covalent bond in anion clusters. Orbital hybridization effect is much stronger for ions with smaller radius. Relatively flat dispersion relations of band structures are indicated the localized bonding state and population analysis provided further information on this aspect. The results of DOS show the valence band near the E-F is all dominated by 2p orbit of carbon atoms and metals play an important role in conduction band. (c) 2007 Elsevier B.V. All rights reserved.