Analysis of Dihydrogen Bonding in Ammonium Borohydride
| Autor: | Jeff Armstrong, Mikael Andersson, Torben R. Jensen, Johan Klarbring, Jakob B. Grinderslev, Sergei I. Simak, Ulrich Häussermann, Maths Karlsson, Stanislav Filippov |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Oorganisk kemi
Materials science Intermolecular force 02 engineering and technology Crystal structure 010402 general chemistry 021001 nanoscience & nanotechnology Borohydride Alkali metal 01 natural sciences Inelastic neutron scattering 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Ion Inorganic Chemistry chemistry.chemical_compound Crystallography General Energy chemistry Libration Density functional theory Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Filippov, S, Grinderslev, J B, Andersson, M S, Armstrong, J, Karlsson, M, Jensen, T R, Klarbring, J, Simak, S I & Häussermann, U 2019, ' Analysis of Dihydrogen Bonding in Ammonium Borohydride ', Journal of Physical Chemistry C, vol. 123, no. 47, pp. 28631-28639 . https://doi.org/10.1021/acs.jpcc.9b08968 |
| DOI: | 10.1021/acs.jpcc.9b08968 |
| Popis: | The structural and vibrational properties of ammonium borohydride, NH4BH4, have been examined by first-principles density functional theory (DFT) calculations and inelastic neutron scattering (INS). The H disordered crystal structure of NH4BH4 is composed of the tetrahedral complex ions NH4+ and BH4-, which are arranged as in the fcc NaCl structure and linked by intermolecular dihydrogen bonding. Upon cooling, the INS spectra revealed a structural transition between 45 and 40 K. The reversible transition occurs upon heating between 46 and 49 K. In the low-temperature form reorientational dynamics are frozen. The libration modes for BH4- and NH4+ are near 300 and 200 cm(-1), respectively. Upon entering the fcc high-temperature form, NH4+ ions attain fast reorientational dynamics, as indicated in the disappearance of the NH4+ libration band, whereas BH4- ions become significantly mobile only at temperatures above 100 K. The vibrational behavior of BH4- ions in NH4BH4 compares well to the heavier alkali metal borohydrides, NaBH4-CsBH4. DFT calculations revealed a nondirectional nature of the dihydrogen bonding in NH4BH4 with only weak tendency for long-range order. Different rotational configurations of complex ions appear quasi-degenerate, which is reminiscent of glasses. Funding Agencies|Nordforsk within the project FunHy; Swedish research council (VR)Swedish Research Council; Carl Tryggers Stiftelse (CTS) for Vetenskaplig Forskning; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971] |
| Databáze: | OpenAIRE |
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