A system with three contiguous planar tetracoordinate carbons is viable: a computational study on a C6H6 isomer

Ab initio and density functional theory calculations indicate that a benzene dication isomer (1: C₆H₆²⁼) with three contiguous planar tetracoordinate carbons is at a minimum on the potential energy surface. The remarkable preference for the planar structure for 1 is traced to the aromatic stabilization present in the three membered ring formed by the three planar tetracoordinate carbon atoms.