It is evident from Table 1 that accumulation of significant electron density between the Be-Be and Zn-Zn bond critical points. The negative values of laplacian of electron density, ∇²ρand total electronic energy density, H (r) suggests significant covalency in the Be-Be bonds. However, the positive value of laplacian of electron density, ∇²ρ and negative value of total electronic energy density, H (r) for Zn-Zn bond suggests polar covalent character. The calculated values of ELF populations, V(M,M) are significantly higher for Be-Be bonds but somewhat smaller for Zn-Zn bonds. The electron population of the Be-Be bond and Zn-Zn bonds obtained through NBO analyses¹⁵ are very close to the value of 1.0 suggesting 2-centre-1-electron interaction. The hybridization of the Be-Be and Zn-Zn bonds have significant ns (2s for Be and 4s for Zn) character supporting covalent nature of these bonds. The contribution of s character decreases slightly for Zn-Zn bonds which has also reflected in the ELF basin populations, V(Zn,Zn) (Table 1). The V(Zn,Zn) values of Zn-Zn bonds are close to 0.7 while they are close to 0.9 for Be-Be bonds. Figure 4 shows the molecular graphs and 3D ELF plots of the compounds.