Boron hydride clusters

Although they have few practical applications, the borane hydride clusters exhibit structures and bonding that differs strongly from the patterns seen in hydrocarbons.

[1] The development of the borane hydride clusters resulted from pioneering work by Alfred Stock, invented the glass vacuum line for their study.

The bonding of the clusters ushered in Polyhedral skeletal electron pair theory and Wade's rules, which can be used to predict the structures of boranes.

For example, in the icosahedral ion [B12H12]2−, the totally symmetric (Ag symmetry) molecular orbital is equally distributed among all 12 boron atoms.

An example: Acidity increases with the size of the borane, with B10H14 having a pKa value of 2.7:[12] In general, bridging hydrogen protons tend to be lost before terminal ones.

This approach also applies to the synthesis of metallaboranes, Reminiscent of the behavior of diborane and its adducts, higher boranes participate in hydroboration.

[16] Boranes have a high specific energy of combustion compared to hydrocarbons, making them potentially attractive as fuels or igniters.

Because 10B has a very high neutron-capture cross section, boron-hydride derivatives have often been investigated for applications in Neutron capture therapy of cancer.