Unexpected Xe anions in XeLin intermetallic compounds

Abstract

The reactivity of Xe is important in both fundamental chemistry and geological science. The discovery of the reductive reactivity of Xe extended the doctrinal boundary of chemistry for which a completed shell is inert to reaction. The oxidation of Xe by various elements has been explored. On the other hand, the opposite chemical inclination, i.e., gaining electrons and forming anions, has not been thoroughly studied for Xe or other noble-gas elements. In this work, we demonstrate, using first-principles calculations and an efficient structure prediction method, that Xe can form stable compounds under high pressure. These compounds are intermetallic and Xe are negatively charged. The stability of these compounds indicates that atoms or ions with completely filled shell may still gain electrons in chemical reactions.