Unraveling the Bonding and Aromaticity of Pentazole, Pentaphosphole, and Cyclopentadiene Anions: A Comprehensive Study

This study investigates π-delocalization, π-bonding situations, and aromaticity of the pentazolate anion ([cyclo-N₅^-], (a)), which was detected by Christe et al. in 2002. To gain a broader perspective, we investigated the iso-π-electronic species [cyclo-P₅^-] (b) and [cyclo-(CH)₅^-] (c). VB analyses reveal that the three studied molecules display significant resonance stabilization, as indicated by their high resonance energy values. A comprehensive analysis of aromaticity was conducted using electronic and magnetic aromaticity indices, revealing that all three anions exhibit strong π-aromaticity and relatively weak σ-aromaticity.