Pentaborane(11)


Pentaborane is inorganic compound with the chemical formula B5H11. It is an obscure boron hydride cluster, especially relative to the heavily studied pentaborane(9). With two more hydrogen atoms than nido-pentaborane, pentaborane is classified as an arachno- cluster.

Synthesis

Like many boron hydride clusters, pentaborane was originally obtained from the pyrolysis of diborane. A more systematic synthesis entails treatment of − with boron tribromide. The Lewis acid abstracts hydride to give unstable B4H8, the precursor to B5H11: