Ab Initio Calculations on Bismuth Cluster Polycations

Ab initio calculations on bismuth polycationic species of the types Bin(n−2)+, Bin(n−4)+, and Bin(n−6)+ (n=3–12) were performed at the Hartree–Fock and density functional theory levels in order to investigate their general properties and the applicability of Wade's rules on bismuth polycations. Some exceptions to Wade's rules were encountered, and, moreover, several predicted and calculated minima show only meta‐stable behavior. The bonding in bismuth polycations is characterized by a high degree of electron delocalization and “three‐dimensional aromaticity”. The diversity of bismuth subvalent compounds is a fascination within cluster chemistry of the main group elements. By the use of natural bonding orbital (NBO) analysis and the electron localization function (ELF) the bonding in small bismuth clusters (an example is shown here), suggested by Wade's rules, has been characterized.