Three-center two-electron bond

An extended version of the 3c–2e bond model features heavily in cluster compounds described by the polyhedral skeletal electron pair theory, such as boranes and carboranes.

These molecules derive their stability from having a completely filled set of bonding molecular orbitals as outlined by Wade's rules.

This bonding pattern is also seen in trimethylaluminium, which forms a dimer Al2(CH3)6 with the carbon atoms of two of the methyl groups in bridging positions.

The first stable subvalent Be complex ever observed contains a three-center two-electron π-bond that consists of donor-acceptor interactions over the C-Be-C core of a Be(0)-carbene adduct.

[4] Carbocation rearrangement reactions occur through three-center bond transition states.

Resonance structures of 3c-2e bond in diborane.
One of many transition metal silane complexes , examples feature three-center two-electron bonding. [ 3 ]