Descriptors of Aromaticity: Magnetic Criteria

In (anti)aromatic molecules, a ring current caused by the movement of delocalized π-electrons is generated when an external magnetic field is applied perpendicular to the plane of the aromatic system. Magnetic indices of aromaticity are based on these rings' currents generated on the (anti)aromatic rings when exposed to external magnetic fields. In this chapter, we discuss the most employed descriptors of aromaticity that are based on magnetic properties.