From symmetrical arguments, the equivalence of MMBs and EDMBs comes from the impossibility of the occurrence of ERMBs in extended solids. According to Lubchenko and coworkers , the multicenter bond becomes electron deficient for any molecule longer than three centers, so the only possible kind of multicenter bonding in extended chains and solids is the EDMB. This is especially clear in crystalline solids, e.g., BaZnSb2 As-II, due to the existence of translational symmetry. As already mentioned, all Sb atoms at the planar array in BaZnSb2 are at 4c sites, so they are all equivalent and must have the same charge (Sb 0.6ꟷ ) . Similarly, all As atoms in the sc phase of As-II are located in the 4a Wyckoff position, so all atoms are equivalent and must have the same charge. In both examples ET = 0, so no ERMBs with high values of ET as those shown in Fig. can be formed by As and Sb atoms in these two solids. The translational symmetry in solids makes it impossible for the central atom of a given hypercoordinated unit in Fig. to shift electronic charge to the external parts of the unit, as it happens in molecules with ERMBs, in which the central atom has always a positive charge because this will require the existence of different Wyckoff sites for the central and external atoms of the smallest trimer molecule represented in Fig. . Different charges for different Wyckoff sites occur for instance in -GeTe with rs structure because Ge and Te are in 4a and 4b sites. Assuming that one of the two elements will have a positive charge and the other one a negative one, let us take , 3c-4e bonds along three perpendicular axes with cubic symmetry as shown in Fig. , could be possible around the positive ion with a Te --Ge  -Te -configuration according to our reasoning of charge distribution (─ + ─) in the I3 ꟷ molecule, but not around the negative ion with Ge  -Te --Ge  configuration. On the other hand, no five-center bond with Te --Ge  -Te --Ge  -Te  configuration or larger ERMBs with equal Ge-Te bond distances could be possible because the central atoms in molecules with ERMBs should exhibit the more positive charges due to the trans influence. It must be noted that linear or quasi-linear ERMBs larger than three centers (4c-6e, 5c-6e, 5c-8e, etc.) have been thoroughly studied, but they do not have the equal or nearly equal bond distances in EDMBs and 3c-4e bonds . The situation is different in molecules, even inside solids, where such symmetry restrictions must not be obeyed. One example is the recent finding of ERMBs in the low-temperature monoclinic phase of crystalline RuP, where linear 3c-4e bonds have been found in molecular Ru-Ru-Ru units (the central and external Ru atoms of the trimer occupy different 4e Wyckoff sites) along zigzag-like ladders . Therefore, we consider that ERMBs with equal bond distances are not possible in linear molecules of more than three atoms inside crystalline solids, thus MMBs in solids cannot be equivalent to ERMBs.