Proton magnetic relaxation in [N(CH3)4]2 ZnCl4

Proton magnetic relaxation in (TMA)2HgBr4 and (TMA)2HgI4

“…The 7"1 minima observed in (TMA)2ZnCI4 were ascribed (Niemela and Heinila 1981) to arise from two inequivalent r~l^ ions. The 7"1 is expected to pass through two minima of equal value (O'ReiUy and Tsang 1967) for (NH4)2SO4, in case the two T~ minima observed were due to the presence of two inequivalent a' •,lA ions.…”

“…(TMA)2ZnCI4 which belongs to the A2BX4 type of compounds is reported to be ferro-electric (Sawada et al 1978). Magnetic resonance and relaxation study (Blinc et al 1979) in (TMA)zZnCI4 revealed reorientational motion of the methyl group and the TMA ion, even at 120 K. Niemela and Heinila (1981) inferred from the temperature dependence of the proton spin lattice relaxation time (7"1) in (TMA)2ZnCI4 that there are two inequivalent TMA ions in this compound. The motional effects in (TMA)2HgBr4 and (TMA)2HgL investigated by proton magnetic relaxation technique are reported in this paper and the results are compared with the motional effects in (TMA)2HgCI4 reported earlier (Sarma and Ramakrishna 1984b).…”

Proton NMR study of molecular dynamics and phase transitions in dimethylammonium hexachloro plumbate [NH2(CH3)2]2PbCl6

“…The T1 behaviour in this phase could be explained assuming the presence of inequivalent methyl groups. The expression for TI for inequivalent ions (Niemela and Heinila, 1981) is where N = N , + Nb + N,, and N,, Nb, N, are the number of type a, type b and type c ions respectively. The T1 behaviour and the TI minimum of 19 msec could be explained in terms of inequivalent methyl groups in the ratio 5:3.…”

Proton NMR Study of Molecular Dynamics and Phase Transitions in Trimethyl Ammonium Hexachloro Plumbate [NH(CH3)3]2PbCl6 and Tetramethyl Ammonium Hexachloro Plumbate [N(CH3)4]2PbCl6

“…In the presence of inequivalent molecular groups, the resultant relaxation rate is given by [18] T À1 1…”

“…The T 1 behaviour in phase II (340 to 119 K), could be explained in terms of inequivalent TrMA ions and inequivalent methyl groups. In the presence of inequivalent molecular groups, the resultant relaxation rate is given by [18] T À1 1…”