Diborane(2) is an inorganic compound having the formula B2H2. It has a symmetric covalently bonded structure of HBBH, with a double bond between the two boron atoms and one hydrogen atom bonded to each boron. This compound is unique among the analogous formulas for other elements of the boron group,[1] and also unlike higher boranes such as diborane(6) (B2H6), in that it has a direct boron–boron bond rather than bridging hydrides. The boron–boron bonding in this compound is also a rare example of a pure pi bond, one that does not have any net sigma bonding associated with it.[2]
^Treboux, Gabin; Barthelat, Jean Claude (1993). "X-X direct bonds versus bridged structures in group 13 X2H2 potential energy surfaces". J. Am. Chem. Soc. 115 (11): 4870–4878. doi:10.1021/ja00064a056.
