SCF calculations utilizing a basis of all s-type Gaussians have been performed to investigate the dimerization of BH3 to B2H6. Localized molecular orbitals and pseudonatural orbitals are calculated. The dimerization energy obtained (11.5 kcal/mole) supports the assumption that the non-Hartree-Fock interactions (electron correlation) play a dominant role (Exp = 40–60 kcal/mole). The energy of the principal type of resonance structure based on the SCF-MO 's of the separated-but-distorted BH3 systems is rigorously calculated and found to be 150 kcal/mole higher in energy than the SCF energy of B2H6. Thus, resonance stabilization (delocalization) is shown to be extremely important to the stability of the “three-center” bonds in B2H6, as has been suspected for many years.
