Structural Phase Transition and Decomposition of XeF under High Pressure and Its Formation of Xe-Xe Covalent Bonds.

Noble gases with inert chemical properties have rich bonding modes under high pressure. Interestingly, Xe and Xe form covalent bonds, originating from the theoretical simulation of the pressure-induced decomposition of XeF, which has yet to be experimentally confirmed. Moreover, the structural phase transition and metallization of XeF under high pressure have always been controversial. Therefore, we conducted extensive experiments using a laser-heated diamond anvil cell technique to investigate the above issues of XeF. We propose that XeF undergoes a structural phase transition and decomposition above 84.1 GPa after laser heating, and the decomposed product XeF contains Xe-Xe covalent bonds. Neither the pressure nor temperature alone could bring about these changes in XeF. With our UV-vis absorption experiment, 4/-XeF was metalized at 159 GPa. This work confirms the existence of Xe-Xe covalent bonds and provides insights into the controversy surrounding XeF, enriching the research on noble gas chemistry under high pressure.