As a summary of this section, we conclude that the MMBs are equivalent to EDMBs since both bonds are described by interacting 2c-1e bonds (multicenter bonds). In fact, it can be considered that the MMBs with the linear or quasi-linear geometries presented in Fig. are the type of unsuported EDMBs that typically occur in solids. We have shown that other compounds, such as SbPO4 or BaZnSb2, this last previously assumed to exhibit ERMBs , are also characterized by EDMBs in one and two dimensions, respectively, that add to the EDMBs in three dimensions found in the octahedrally-coordinated phases of pnictogens and chalcogens. We have also proposed that the above mentioned EDMBs seem to be the same type of bond in atomic/polymeric nitrogen and hydrogen at HP since the mechanism of formation of the secondary, intermolecular bonds is the same for nitrogen, hydrogen, B2H6, and MMBs in groupand -16 elements as well as in PCMs. These examples contrast with materials with ERMBs that not only are located in a different position in the 2D ES vs. ET map, but also show a completely different mechanism of formation. We have additionally justified that in extended solids hypercoordination is only possible for EDMBs since ERMBs can only be formed in molecular solids due to energetic and symmetry restrictions. We have shown that linear or quasilinear hypercoordinated multicenter units (both with ERMBs and EDMBs) around a central A atom have geometries compatible with the VSEPR theory and are not hypervalent. We suggest that the "hypervalent" units should be renamed as "hypercoordinated multicenter units" and propose a minimum set of linear multicenter bonds for atoms with p-type orbitals in Fig. with a notation to understand the geometry of the different hypercoordinated multicenter units. Finally, we have reasoned that the doublet/octet rule is satisfied around the central A atom in hypercoordinated units with EDMBs.