Ab initio molecular orbital theory was used to examine the hydrogenation of a B12N12 molecule. The 1,2 addition of the 4,6 bond is an energetically favorable adsorption site in one-hydrogen-molecule adsorption. We found that the averaged bind energy of hydrogen molecule is maximized in B12N12H12. The largest energy gaps of B12N12N12 and B12N12H24 suggest they have special stability. Moreover, calculation of the Gibbs free energy of the B12N12 + 12H(2) -> B12N12H24 reaction showed that this reaction becomes endothermic above 320 K. (c) 2006 Elsevier B.V. All rights reserved.