Aromatic cages B 0/+42: unprecedented existence of octagonal holes in boron clusters

Abstract

The cage-like structures containing octagonal holes are located as the lowest-lying isomers for the B^0/+₄₂. The presence of octagonal holes, which have been found for the first time, not only gives us new insight into the bonding motif, but also marks a breakthrough in the structural characteristics of boron clusters since they were never expected to be stable units for elemental clusters. These cages are composed of both delocalized σ and π electron systems that consequently make them aromatic and thermodynamically stable.