Anion Reorientations in the Superionic Conducting Phase of Na2B12H12

作者：Verdal Nina^*; Udovic Terrence J; Stavila Vitalie; Tang Wan Si; Rush John J; Skripov Alexander V

来源：Journal of Physical Chemistry C, 2014, 118(31): 17483-17489.

DOI：10.1021/jp506252c

Quasielastic neutron scattering (QENS) methods were used to characterize the reorientational dynamics of the dodecahydro-closo-dodecaborate (B12H122-) anions in the high-temperature, superionic conducting phase of Na2B12H12. The icosahedral anions in this disordered cubic phase were found to undergo rapid reorientational motions, on the order of 10(11) jumps s(-1) above 530 K, consistent with previous NMR measurements and neutron elastic-scattering fixed-window scans. QENS measurements as a function of the neutron momentum transfer suggest a reorientational mechanism dominated by small-angle jumps around a single axis. The results show a relatively low activation energy for reorientation of 259 meV (25 kJ mol(-1)).

• 出版日期2014-8-7