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arXiv · 2007.09472

Novel hydrogen clathrate hydrate

Yu Wang·Konstantin Glazyrin·Valery Roizen·Artem Oganov·Ivan Chernyshov·Xiao Zhang·Eran Greenberg·Vitali B. Prakapenka·Xue Yang·Shu-qing Jiang·Alexander F. Goncharov
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Abstract

We report a new hydrogen clathrate hydrate synthesized at 1.2 GPa and 298 K documented by single-crystal X-ray diffraction, Raman spectroscopy, and first-principles calculations. The oxygen sublattice of the new clathrate hydrate matches that of ice II, while hydrogen molecules are in the ring cavities, which results in the trigonal R3c or R-3c space group (proton ordered or disordered, respectively) and the composition of (H2O)6H2. Raman spectroscopy and theoretical calculations reveal a hydrogen disordered nature of the new phase C1', distinct from the well-known ordered C1 clathrate, to which this new structure transforms upon compression and/or cooling. This new clathrate phase can be viewed as a realization of a disordered ice II, unobserved before, in contrast to all other ordered ice structures.

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Yu Wang, Konstantin Glazyrin, Valery Roizen, Artem Oganov, Ivan Chernyshov, Xiao Zhang, Eran Greenberg, Vitali B. Prakapenka, Xue Yang, Shu-qing Jiang, Alexander F. Goncharov. 2020-07-18. Novel hydrogen clathrate hydrate. https://doi.org/10.1103/physrevlett.125.255702

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