Theoretical investigation on the structure and stability of some neutral noble gas compounds containing Xe-Xe bond

DFT calculations are performed to investigate the structure, stability, and nature of chemical bonding of some neutral noble gas insertion compounds containing a Xe-Xe bond; including HXeXeR, FXeXeR as well as RXeXeR (R = CN, NC, CCH, and BS). Geometry optimization of the considered molecules anticipate the existence of just four stable compounds (HXeXeCN, HXeXeNC, FXeXeCN, and FXeXeCCH); and rest of the molecules dissociate during the structural optimization. The results of NBO and AIM calculations show that a H(F)XeXeR molecule has a covalent H(F)-Xe bond in the H(F)XeXe⁺ fragment, which is bonded to R⁻ mainly through columbic interaction. Thermodynamic study indicates that all of the considered unimolecular dissociation channels for decomposition of H(F)XeXeR molecules to neutral fragments are both exothermic and exorergic; but dissociation to ionic species (H(F)XeXe⁺ and R⁻) is endothermic. Also kinetic study of the most probable dissociation reaction shows that FXeXeR molecules are metastable with respect to the global minimum F-R + 2Xe. Therefore, FXeXeCN molecule is more kinetically protected against the decomposition reaction than the other molecules and its experimental detection is more likely.