A growing body of theoretical and experimental evidence suggests that inert gases (He, Ne, Ar, Kr, Xe, Rn) become less and less inert under increasing pressure. Here we use the ab initio evolutionary algorithm to predict stable compounds of Xe and Na at pressures below 100 GPa, and find three stable compounds, NaXe, NaXe3 and NaXe4. The NaXe belongs to a well-known cubic CsCl structure type. The NaXe4's structure is common in amphiboles, whereas the NaXe3 has a unique structure, analogous to the "post-perovskite" orthorhombic CaIrO3-type structure with Ir atoms removed. This is the first time that a cation-vacant version of the CaIrO3 is found in any compound. NaXe, NaXe3 and NaXe4 are found to be metallic.
@article{arxiv.2203.06815,
title = {Stability of xenon-sodium compounds at moderately low pressures},
author = {Shaoxiong Wang and Huafeng Dong and Junhao Peng and Minru Wen and Xin Zhang and Fugen Wu and Alexander F. Goncharov and Artem R. Oganov},
journal= {arXiv preprint arXiv:2203.06815},
year = {2023}
}