A deeper understanding of the MMB formation mechanism can be obtained if the reciprocalspace (band) picture is complemented by the real-space (bond) picture . In particular, the analysis of the ELF topology is a good tool for understanding the formation of secondary bonds, as already shown for CO2 . Therefore, we have analyzed the ELF isosurfaces corresponding to the values of the secondary bonds in which LEPs for the studied elements at different pressures are involved (Fig. ). In group-15 elements, each atom in the layered A7 structure at RP (stage 1) is characterized by a single ELF attractor perpendicular to the layers corresponding to the LEP (Fig. ). This single-basin LEP is formed by s-type orbitals, and it is not aligned along any of the three secondary bonds of the A7 structure. At a certain pressure, the s-type LEP dissociates or splits into three similar lobes (onset of stage 2) that properly align with the directions of the three secondary bonds (Fig. ). At Pt (upon the A7-to-Ah PT), the new three lobes along the secondary bonds become equal to the primary bonds, which marks the onset of stage 3. At this stage, six lobes appear around each atom corresponding to the three pairs of MMBs in the Ah phase (Fig. ). It is important to mention that six equal ELF lobes are also present in α-Po at RP. Moreover, six ELF attractors of similar size to those of the Ah phase in As are also observed in Bi-II (Fig. ), thus confirming that Bi-II already exhibits asymmetric MMBs. Therefore, we conclude that six equal ELF attractors are characteristic of fully symmetric MMBs in the hypercoordinated multicenter unit with cubic symmetry shown in Fig. .