Nuclear magnetic resonance studies of atomic motion in borohydrides

Two basic types of thermally activated atomic jump motion are known to exist in solid borohydrides: the fast reorientations of BH(4) groups and the slower translational diffusion of cations and anions. This paper reviews recent progress in nuclear magnetic resonance (NMR) studies of both these jump processes. It is shown that, for some borohydrides, NMR measurements of the nuclear spin-lattice relaxation can trace the changes in the reorientational jump rates over the range of eight orders of magnitude (10(4) to 10(12) s(-1)). Such a wide dynamic range leads to the high precision of the activation energies for BH(4) reorientations, as derived from the nuclear spin-lattice relaxation measurements. (C) 2010 Elsevier B.V. All rights reserved.