Polyhydride CeH<sub>9</sub> with an atomic-like hydrogen clathrate structure.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31371729.
- Also identified by DOI 10.1038/s41467-019-11330-6 and PMC identifier 6671988.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Compression of hydrogen-rich hydrides has been proposed as an alternative way to attain the atomic metallic hydrogen state or high-temperature superconductors. However, it remains a challenge to get access to these states by synthesizing novel polyhydrides with unusually high hydrogen-to-metal ratios. Here we synthesize a series of cerium (Ce) polyhydrides by a direct reaction of Ce and H<sub>2</sub> at high pressures. We discover that cerium polyhydride CeH<sub>9</sub>, formed above 100 GPa, presents a three-dimensional hydrogen network composed of clathrate H<sub>29</sub> cages. The electron localization function together with band structure calculations elucidate the weak electron localization between H-H atoms and confirm its metallic character. By means of Ce atom doping, metallic hydrogen structure can be realized via the existence of CeH<sub>9</sub>. Particularly, Ce atoms play a positive role to stabilize the sublattice of hydrogen cages similar to the recently discovered near-room-temperature lanthanum hydride superconductors.