Neither too Classic nor too Exotic: One‐Electron Na⋅B Bond in NaBH 3 − Cluster

It is here reported that the NaBH 3 − cluster exhibits a Na⋅B one‐electron bond, a well‐established type of electron‐deficient bonding in the literature. The topological analysis of the electron localization function, at the correlated level, reveals that Na − , when approaching the bonding distance, fairly distributes its valence electron pair between two lobes. One of these electrons is used to bond with BH 3 , which participates through its boron empty p ‐orbital. Furthermore, the bonding situation of LiBH 3 − , KBH 3 − , MgBH 3 , and CaBH 3 global minima structures are similar to that of NaBH 3 − , extending the family of these new one‐electron bond systems with biradicaloid character.