| Autor: |
Henry Auer, Fangshun Yang, Helen Y. Playford, Thomas C. Hansen, Alexandra Franz, Holger Kohlmann |
| Jazyk: |
angličtina |
| Rok vydání: |
2019 |
| Předmět: |
|
| Zdroj: |
Inorganics, Vol 7, Iss 9, p 106 (2019) |
| Druh dokumentu: |
article |
| ISSN: |
2304-6740 |
| DOI: |
10.3390/inorganics7090106 |
| Popis: |
The crystal structure of the Zintl phase hydride CaSiH≈4/3 was discussed controversially, especially with respect to the nature of the silicon-hydrogen interaction. We have applied X-ray and neutron powder diffraction as well as total neutron scattering on a deuterated sample, CaSiD1.1. Rietveld refinement (CaSiD1.1, Pnma, a = 14.579(4) Å, b = 3.8119(4) Å, c = 11.209(2) Å) and an analysis of the neutron pair distribution function show a silicon-deuterium bond length of 1.53 Å. The Si−H bond may thus be categorized as covalent and the main structural features described by a limiting ionic formula Ca2+H−(Si−)2/3(SiH−)1/3. Hydrogen atoms decorating the ribbon-like silicon polyanion made of three connected zigzag chains are under-occupied, resulting in a composition CaSiH1.1. Hydrogen-poor Zintl phase hydrides CaSiH with hydride ions in Ca4 tetrahedra only were found in an in situ neutron diffraction experiment at elevated temperature. Hydrogen (deuterium) uptake and release in CaSiDx (0.05 ≤ x ≤ 0.17) is a very fast process and takes less than 1 min to complete, which is of importance for possible hydrogen storage applications. |
| Databáze: |
Directory of Open Access Journals |
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