A nuclear magnetic resonance study of molecular motion in solid tris(n-propylammonium)enneachlorodiantimonate (III) (n-C3H7NH3)3Sb2Cl9

Proton magnetic resonance second moment and spin-lattice relaxation time were carried out on polycrystalline tris (n-propylammonium) enneachlorodiantimonate (III), (n-C3H7NH3)(3)Sb2Cl9, in the temperature range of 10-370 K. The second moment measurements show that the structure is not rigid on the NMR scale at 10 K, the lowest temperature studied, and that CH3 and NH3 groups execute rotations about C-3 axis. The proton spin-lattice relaxation measurements reveal two minima due to the motions of the amino and methyl groups. Analysis of the relaxation data yields the activation energy barriers of 11.0 kJ mol(-1) and 5.8 kJ mol(-1), respectively, for the NH3 and CH3 groups' motion. NMR data confirm the phase transition at T-c = 232 K, known from different studies. (C) 1997 Elsevier Science B.V.