Babanova, Olga A.
[Ural Division of the Russian Academy of Sciences (Russia)]
Soloninin, Alexei V.
[Ural Division of the Russian Academy of Sciences (Russia)]
Skripov, Alexander V.
[Ural Division of the Russian Academy of Sciences (Russia)]
Ravnsbaek, Dorthe B.
[Aarhus University (Denmark)]
Jensen, Torben R.
[Aarhus University (Denmark)]
Filinchuk, Yaroslav
[UCL]
To study the reorientational motion of the BH4 groups in RbBH4 and CsBH4, we have performed nuclear magnetic resonance (NMR) measurements of the H-1 and B-11 spin-lattice relaxation rates in these compounds over wide ranges of temperature (48-400 K) and resonance frequency (14-90 MHz). It is found that at low temperatures the reorientational motion in CsBH4 is the fastest among all of the borohydrides studied so far. The activation energies E-a for BH4 reorientations obtained from our data are 138 +/- 4 meV for RbBH4 and 105 +/- 7 meV for CsBH4. Investigating the systematics of E-a variations in alkali-metal borohydrides MBH4, we have found a correlation between E-a and the relative deviation of the actual M-B distance from the sum of the ionic radii of M and BH4.
Bibliographic reference |
Babanova, Olga A. ; Soloninin, Alexei V. ; Skripov, Alexander V. ; Ravnsbaek, Dorthe B. ; Jensen, Torben R. ; et. al. Reorientational Motion in Alkali-Metal Borohydrides: NMR Data for RbBH4 and CsBH4 and Systematics of the Activation Energy Variations. In: The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces, Vol. 115, no. 20, p. 10305-10309 (2011) |
Permanent URL |
http://hdl.handle.net/2078/75805 |