1. Raisins in a Hydrogen Pie: Ultrastable Cesium and Rubidium Polyhydrides
- Author
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Zhou, Di, Semenok, Dmitrii V., Galasso, Michele, Alabarse, Frederico Gil, Sannikov, Denis A., Troyan, Ivan A., Nakamoto, Yuki, Shimizu, Katsuya, and Oganov, Artem R.
- Subjects
Condensed Matter - Materials Science ,Condensed Matter - Soft Condensed Matter - Abstract
We proposed a new method for synthesis of metal polyhydrides via high-pressure thermal decomposition of corresponding amidoboranes in diamond anvil cells. Within this approach, we synthesized molecular semiconducting cesium ($\textit P4/nmm$-CsH$_7$, $\textit P$1-CsH$_{15+x}$) and rubidium (RbH$_{9-x}$) polyhydrides with a very high hydrogen content reaching 93 at%. Preservation of CsH$_7$ at near ambient conditions, confirmed both experimentally and theoretically, represents a significant advance in the stabilization of hydrogen-rich compounds. In addition, we synthesized two crystal modifications of RbH$_{9-x}$ with pseudo hexagonal and pseudo tetragonal structures identified by synchrotron X-ray diffraction and Raman measurements. Both phases are stable at 8-10 GPa. This is an unprecedented low stabilization pressure for polyhydrides. These discoveries open up possibilities for modifying existing hydrogen storage materials to increase their efficiency.
- Published
- 2024
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