Other names: diborane(6)
Diborane is a dimer of the molecule boron hydride borane (BH3) and the simplest of a much larger family of borane cluster compounds.. Like many trivalent Group III species, borane possesses an empty p orbital at boron, rendering it a powerful Lewis acid. Its thermodynamic craving for electronic density to fill this vacancy ultimately leads to the formation of diborane, as two molecules of borane will coordinate each other pairwise with σ(B-H) bonding orbitals coordinating into vacant B(2p) orbitals to form diborane. This interaction may be depicted either by a bridging divalent hydrogen (as shown here) or as a "banana bond" to accentuate the 3-center-2-electron nature of the B-H-B bond.