In 2023, the two current bonding models of PCMs have been defended by their supporters . On one hand, Wuttig and coworkers have suggested that metavalent bonds cannot be ERMBs, as suggested by Jones . Wuttig and coworkers have calculated the ES value between two atoms, as two times the delocalization index , in molecules with well-known hypervalent ERMBs or 3c-4e bonds, such as XeF2 and SF4 molecules, and have evidenced that they present ES values between 1.5 and 2, i.e. similar to those of covalent bonds. This result differs from the ES values obtained for materials with metavalent bonding (ES ≈ 1), so they have shown that molecules with ERMBs are located in a different position than incipient metals in Wuttig's ES vs. ET map . In this respect, Wuttig and coworkers left open the door for metavalent bonds to be equivalent to charge-shift bonds , or even to electron-deficient multicenter bonds (EDMBs). In particular, EDMBs are akin to three-center-two-electron (3c-2e) bonds present in boranes and in solids, such as boron , boron-based compounds , intermetallics , and some aluminosilicates . Contrarily, Jones et al. insisted that metavalent bonds are indeed ERMBs and that the ES value is not a good parameter to describe the unconventional bonding in PCMs. These authors argue that the Wuttig's ES vs. ET map is not useful for materials with different kinds of bonds in their crystalline structures , e.g. the case of the amorphous phases of PCMs and of crystalline IV-VI and V2-VI3 materials showing a mixture of conventional 2c-2e bonds and unconventional bonds at RP. In summary, the dispute regarding the nature of the unconventional bonding in PCMs is unresolved.