Analyzing bonding pattern of BxNx clusters via Adaptative Natural Density Partitioning (AdNDP)
For a more detailed analysis regarding the aromaticity and chemical bond in BxNx clusters, AdNDP was performed, representative cases (antiaromatic, aromatic and non-aromatic) are shown in Fig. 6 and Fig. 7, the remaining systems can be seen in the supporting information.
The bonding pattern for B2N2 (Fig. 6) starts with four 2c-2e B-N σ bonds, it is necessary to note that the bonds are polarized towards N atoms mainly due to their high electronegativities regarding B atoms. In addition, two σ- and two π- delocalized 4c-2e bonds fullfilling electron counting rules which confirms their doubly aromatic character.