H NMR Study of Ionic Motions in High Temperature Solid Phases of (CH3NH3)2ZnCl4

The reorientation of the tetrahedral complex anion ZnCl 4 2 and the self-diffusion of the cation in (CH3NH3)2ZnCl4 were studied by 'H NMR spin-lattice relaxation time ( 'H TX) experiments. In the second highest-temperature phase, the temperature dependence of *H TX observed at 8.5 MHz could be explained by a magnetic dipolar-electric quadrupolar cross relaxation between 'H and chlorine nuclei, and the activation energy of the anion motion was determined to be 105 kJ m o l 1 . In the highest-temperature phase, the activation energy of the self-diffusion of the cation was determined to be 58 kJ m o l 1 from the temperature and frequency dependence of 'H TX.