Bonding analysis of planar hypercoordinate atoms via the generalized BLW-LOL

The multicenter bonding pattern of the intriguing hexa-, hepta-, and octacoordinate boron wheel series (e.g., CB62-, CB7-, B82-, and SiB8 as well as the experimentally detected CB7- isomer) is revised using the block-localized wave function analyzed by the localized orbital locator (BLW-LOL). The more general implementation of BLW combined with the LOL scalar field is not restricted to the analysis of the out-of-plane π-system but can also provide an intuitive picture of the σ-radial delocalization and of the role of the central atom. The results confirm the presence of a π-ring current pattern similar to that of benzene. In addition, the LOLπ isosurfaces along with the maximum intensity in the ΔLOL profiles located above and below the ring suggest that the central atom plays a minor role in the π-delocalized bonding pattern. Finally, the analysis of the σ-framework in these boron wheels is in line with a moderated inner cyclic rather than disk-type delocalization.