New high-pressure van der Waals compound Kr(H2)4 discovered in the krypton-hydrogen binary system
説明
<jats:title>Abstract</jats:title><jats:p>The application of pressure to materials can reveal unexpected chemistry. Under compression, noble gases form stoichiometric van der Waals (vdW) compounds with closed-shell molecules such as hydrogen, leading to a variety of unusual structures. We have synthesised Kr(H<jats:sub>2</jats:sub>)<jats:sub>4</jats:sub> for the first time in a diamond-anvil high-pressure cell at pressures ≥5.3 GPa and characterised its structural and vibrational properties to above 50 GPa. The structure of Kr(H<jats:sub>2</jats:sub>)<jats:sub>4</jats:sub>, as solved by single-crystal synchrotron X-ray diffraction, is face-centred cubic (fcc) with krypton atoms forming isolated octahedra at fcc sites. Rotationally disordered H<jats:sub>2</jats:sub> molecules occupy four different, interstitial sites, consistent with the observation of four Raman active H<jats:sub>2</jats:sub> vibrons. The discovery of Kr(H<jats:sub>2</jats:sub>)<jats:sub>4</jats:sub> expands the range of pressure-stabilised, hydrogen-rich vdW solids, and, in comparison with the two known rare-gas-H<jats:sub>2</jats:sub> compounds, Xe(H<jats:sub>2</jats:sub>)<jats:sub>8</jats:sub> and Ar(H<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>, reveals an increasing change in hydrogen molecular packing with increasing rare gas atomic number.</jats:p>
収録刊行物
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- Scientific Reports
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Scientific Reports 4 (1), 4989-, 2014-05-16
Springer Science and Business Media LLC