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- Title
Structure and Composition of the 200 K-Superconducting Phase of H<sub>2</sub>S at Ultrahigh Pressure: The Perovskite (SH<sup>−</sup>)(H<sub>3</sub>S<sup>+</sup>).
- Authors
Gordon, Elijah E.; Whangbo, Myung-Hwan; Xu, Ke; Xiang, Hongjun; Bussmann-Holder, Annette; Kremer, Reinhard K.; Simon, Arndt; Köhler, Jürgen
- Abstract
At ultrahigh pressure (>110 GPa), H2S is converted into a metallic phase that becomes superconducting with a record Tc of approximately 200 K. It has been proposed that the superconducting phase is body-centered cubic H3S (Im m, a=3.089 Å) resulting from the decomposition reaction 3 H2S→2 H3S+S. The analogy between H2S and H2O led us to a very different conclusion. The well-known dissociation of water into H3O+ and OH− increases by orders of magnitude under pressure. H2S is anticipated to behave similarly under pressure, with the dissociation process 2 H2S→H3S++SH− leading to the perovskite structure (SH−)(H3S+). This phase consists of corner-sharing SH6 octahedra with SH− ions at each A site (the centers of the S8 cubes). DFT calculations show that the perovskite (SH−)(H3S+) is thermodynamically more stable than the Im m structure of H3S, and suggest that the A site hydrogen atoms are most likely fluxional even at Tc .
- Subjects
SUPERCONDUCTING composites; ULTRAHIGH pressure metamorphism; PEROVSKITE; CHEMICAL decomposition; ANALOGY in science education
- Publication
Angewandte Chemie International Edition, 2016, Vol 55, Issue 11, p3682
- ISSN
1433-7851
- Publication type
Article
- DOI
10.1002/anie.201511347