Planar pentacoordinate zinc group elements, (M = Zn, Cd, Hg) were computationally found to be at a global minimum in Li5M+ clusters. The stability of these clusters is due to the presence of multicentric bonds. The central element (Zn, Cd, Hg) in each cluster features a negative oxidation state owing to the in-plane electron donation by the Li5 + framework. A similar global minimum planar pentacoordinate structure is found in Na5Zn+ and Na5Cd+ clusters.

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Quantum chemical calculations have been carried out to investigate the possibility of Group 12 (Zn, Cd, Hg) dimer formation supported by the B3 ring. All these complexes have significantly shorter M‐M (M = Zn, Cd, Hg) distances compared to their bare dimers, M2. The staggered and eclipsed forms of these complexes were found to be nearly degenerate. They have significant bond strengths as revealed from the significantly higher values of Wiberg bond indices as well as bond dissociation energies. The topological feature of electron density reveals significant covalency in the M‐M interaction which has also been confirmed from natural orbital for chemical valence analysis coupled with extended transition state (ETS‐NOCV) calculations.

Planar hypercoordinate structures are gaining immense attention due to the shift from common paradigm. Herein, our high level ab initio calculations predict that planar pentacoordinate aluminium and gallium centres in Cu5Al2+ and Cu5Ga2+ clusters are global minima in their singlet ground states. These clusters are thermodynamically and kinetically very stable. Detailed electronic structure analyses reveal the presence of σ-aromaticity which is the driving force for the stability of the planar form.

The multifaceted little Na−B bond in NaBH3‐ cluster has been the subject of many recent studies. Many proposals have been put forward for the complete understanding of the chemical bonding in NaBH3‐ cluster. However, none of the studies provided a complete picture. Herein, the missing recipe of the chemical bonding in NaBH3‐ cluster has been identified which completes the description. Our calculations reveal that the chemical bonding in NaBH3‐ cluster is more multifaceted than ever thought. Our finding suggests that the NaBH3‐ cluster features a Na−B one electron bond which is assisted by three 3‐centre‐2‐electron Na‐B−H bond. Detailed topological analyses of electron density and electron localization function at the correlated level reveal such a bonding situation. This missing 3‐centre‐2‐electron Na‐B−H bond completes the description of chemical bonding in NaBH3‐ cluster which is at‐per with the well established bonding scenario for electron deficient compounds. Similar bonding scenario is observed in KBH3−, CuBH3‐ and AuBH3− clusters, further lending support to the complete picture of bonding.