The band structure and density-of-states were calculated by using the LCAO method. It was found that the compound had several Fermi surfaces (figures 16 to 18), in spite of there being an even number of valence electrons in the molecule. Population analysis revealed a substantial degree of electron transfer from the Mg atom to the B atoms.

Electronic Band Structure of Magnesium Diboride. D.R.Armstrong, P.G.Perkins: Journal of the Chemical Society, Faraday Transactions - 2, 1979, 75[1], 12-6

Figure 16

Fermi Surface for MgB2 in the Third Band