The nature of the hexacoordinated carbon in the pentagonal-pyramidal benzene and hexamethylbenzene dications was investigated using the Atoms in Molecules (AIM's analysis) and the electron localization function (ELF) analysis. The following conclusions were reached from the AIM analysis: (i) six bond critical points linked to the apical carbon atom were found; (ii) at the equilibrium geometry, no cage critical point was observed; and (iii) Bader's charges are consistent with a cyclopentadiene cation linked to a [C-R]+ fragment. The topological analysis of the ELF shows a near ring basin between the apical carbon and the pentadiene ring.
