Anionic Chemistry of Noble Gases: Formation of Mg-NG (NG = Xe, Kr, Ar) Compounds under Pressure

作者：Miao Mao sheng^*; Wang Xiao li; Brgoch Jakoah; Spera Frank; Jackson Matthew G; Kresse Georg; Lin Hai qing

来源：Journal of the American Chemical Society, 2015, 137(44): 14122-14128.

DOI：10.1021/jacs.5b08162

While often considered to be chemically inert, the reactivity of noble gas elements at elevated pressures is an important aspect of fundamental chemistry. The discovery of Xe oxidation transformed the doctrinal boundary of chemistry by showing that a complete electron shell is not inert to reaction. However, the reductive propensity, i.e., gaining electrons and forming anions, has not been proposed or examined for noble gas elements. In this work, we demonstrate, using first-principles electronic structure calculations coupled to an efficient structure prediction method, that Xe, Kr, and Ar can form thermodynamically stable compounds with Mg at high pressure (>= 125, >= 250, and >= 250 GPa, respectively). The resulting compounds are metallic and the noble gas atoms are negatively charged, suggesting that chemical species with a completely filled shell can gain electrons, filling their outermost shell(s). Moreover, this work indicates that Mg(2)NG (NG = Xe, Kr, Ar) are high-pressure electrides with some of the electrons localized at interstitial sites enclosed by the surrounding atoms. Previous predictions showed that such electrides only form in Mg and its compounds at very high pressures (>500 GPa). These calculations also demonstrate strong chemical interactions between the Xe 5d orbitals and the quantized interstitial quasiatom (ISQ) orbitals, including the strong chemical bonding and electron transfer, revealing the chemical nature of the ISQ.

• 出版日期2015-11-11
• 单位北京计算科学研究中心