  Aromaticity is one of the most widely used chemical concepts. Current
definitions are purely phenomenological and relate symmetry, reactive stability
and the occurence of molecular diamagnetic response currents. The antithetical
concept of antiaromaticity provides a connection between the contrary
properties of structural instability or distortion out of higher symmetry, a
small HOMO-LUMO gap, and paramagnetic response currents. We reveal the
principle that is underlying antiaromaticity in showing an intimate and strict
symmetry induced relation between these properties. This principle can be
proven and is formulated like: First order (and related) Jahn-Teller distorted
molecules out of non-isometric point groups are prone to paramagnetic current
susceptibility parallel to the main axis of symmetry. We show by the exemplary
cases of cyclobutadiene, cylcooctatetraene, pentalene and manganese trifluoride
how this principle works and discuss this new perspective on antiaromaticity.
