Bismuth polycations

[2] It has since been found that these clusters are present in the solid state, particularly in salts where germanium tetrachloride or tetrachloroaluminate serve as the counteranions, but also in amorphous phases such as glasses and gels.

Bismuth polycations form despite the fact that they possess fewer total valence electrons than would seem necessary for the number of sigma bonds.

The shapes of these clusters are generally dictated by Wade's rules, which are based on the treatment of the electronic structure as delocalized molecular orbitals.

This behavior is possible due to the otherwise fairly inert lone pairs on each of the bismuth that arise primarily from the s-orbitals left out of Bi–Bi bonding.

The variety of electron-deficient sigma aromatic clusters formed by bismuth gives rise to a wide range of spectroscopic behaviors.