Energetic aspects of cyclic Pi-electron delocalization: Evaluation of the methods of estimating aromatic stabilization energies

An overview is given of the aromatic stabilization in pi-electrons. Topics discussed include delocalization versus localization, aromaticity, resonance energy, and mono- or multidimensional perspective of π-electron delocalization description. Under aromaticity, the energetic, geometric, magnetic, and reactivity criteria are described. In resonance energy, the valence bond approach as well as the experimental and theoretical approaches are outlined.