Diborane is the compound consisting of B and H with the formula B2H6. It is a colorless, highly unstable and gas at room temperature with a repulsively sweet odor.
Diborane mixes well with air, easily forming explosive mixtures. Diborane will ignite spontaneously in moist air at room temperature. Synonyms include boroethane, boron hydride, and diboron hexahydride.
Writing the structure of diborane:
Having used two electrons in bonding to the terminal hydrogen atoms, each boron has one valence electron remaining for additional bonding. The bridging hydrogen atoms provide one electron each. Thus the B2H2 ring is held together by four electrons.