Inconsistency of the Ring Current Model for the Cyclopropenyl Cation

We present results of a quantum-mechanical calculation of electron current density, magnetic susceptibility and proton magnetic shielding in the cyclopropenyl cation, reflecting on the ring-current model. The current density induced in and out of the molecular plane by a perpendicular magnetic field is plotted, showing the existence of localized distributions and paramagnetic circulations around the centre of the molecule.