Synthesis and Stability of Lanthanum Superhydrides
[1];
- Geophysical Laboratory Carnegie Institution of Washington Washington DC 20015 USA
- Geophysical Laboratory Carnegie Institution of Washington Washington DC 20015 USA, Permanent address: HP&,SRPD Bhabha Atomic Research Center Mumbai-85 India
- HPCAT Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
- Institute of Materials Science and Department of Civil and Environmental Engineering The George Washington University Washington DC 20052 USA
Abstract Recent theoretical calculations predict that megabar pressure stabilizes very hydrogen‐rich simple compounds having new clathrate‐like structures and remarkable electronic properties including room‐temperature superconductivity. X‐ray diffraction and optical studies demonstrate that superhydrides of lanthanum can be synthesized with La atoms in an fcc lattice at 170 GPa upon heating to about 1000 K. The results match the predicted cubic metallic phase of LaH 10 having cages of thirty‐two hydrogen atoms surrounding each La atom. Upon decompression, the fcc‐based structure undergoes a rhombohedral distortion of the La sublattice. The superhydride phases consist of an atomic hydrogen sublattice with H−H distances of about 1.1 Å, which are close to predictions for solid atomic metallic hydrogen at these pressures. With stability below 200 GPa, the superhydride is thus the closest analogue to solid atomic metallic hydrogen yet to be synthesized and characterized.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1416987
- Journal Information:
- Angewandte Chemie (International Edition), Journal Name: Angewandte Chemie (International Edition) Vol. 57 Journal Issue: 3; ISSN 1433-7851
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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