8. The EDMBs in solids will be easily recognized by the scientific community if clear observables are defined for incipient metals. We have proposed that one of the easiest ways to evidence the change from the pre-MMB scenario to the MMB scenario at HP is by detecting the normal hardening of the previous soft optical modes observed in covalent ppσ-bond materials. This will occur simultaneously with a normal decrease of the bond distance as expected in stage 3 of the mechanism of EDMB formation. In this sense, we have come up with the idea that soft optical modes in p-type materials are the signature of the instability of the ionocovalent ppσ-bonds at HP, in a similar way as soft acoustic modes at the Brillouin zone edges are the signature of the instability of ionocovalent sp 3 σ-bonds. Additionally, we have commented that EDMBs are longer than covalent bonds. It has been estimated that EDMBs are 1.2 to 1.3 times larger than covalent bonds at the same pressure/temperature conditions. On the other hand, EDMBs have ca. half the electronic charge of covalent bonds since they have ca. half ES values, thus EDMBs should have typical charge densities 60 to 65% smaller than covalent bonds. These descriptors can help researchers identifying EDMBs in solids. For instance, formation of EDMBs is expected to occur in iodates at HP since recent studies have evidenced the equalization of the short and long I-O bonds with increasing pressure that are concomitant with the softening of high-frequency optical phonons . 9. Based on ES values (ES ≈ 1), on the mechanism of MMB formation, and energy and symmetry arguments, we have shown that MMBs in PCMs and group-15 and -16 elements are equivalent to the EDMBs of diborane and of atomic/polymeric nitrogen and hydrogen at HP, despite in these materials there could be no LEPs and even no p-type electrons. In addition to molecules, we have shown that EDMBs are also present in solids as extended linear chains of hypercoordinated atoms along one, two, and three directions. For instance, we have reasoned it for several solids: SbPO4 (1D), BaZnSb2 (2D), and the Ah and Ai phases of group-15 and -16 elements (3D). Some of these examples were previously assumed to exhibit ERMBs. The MMB is thus not equivalent to ERMB; a bond present in hypercoordinated molecules, such as I3 ꟷ , XeF2, XeF4, XeF6, and in molecular solids, such as CsI3 and Cs2TeI6, but not forming extended chains in solids neither in one, two, nor three dimensions. The similarity between MMBs and EDMBs and the dissimilarity with ERMBs is patent in the ES vs. ET map. . Units with linear or quasi-linear ERMBs or EDMBs fulfill the VSEPR theory. In all of them, the 8 -N rule is not obeyed but the doublet/octet rule is in general satisfied for EDMDs. We have proposed that "hypervalent units", in which linear or quasi-linear ERMBs or EDMBs in one, two, or three dimensions are present, should be renamed as "hypercoordinated multicenter units". Moreover, we have suggested a new notation for these hypercoordinated units based on the number of ionocovalent bonds, LEPs, and multicenter bonds.