Pk. Rajan et al., PHASE-TRANSITIONS AND CATION DYNAMICS IN [(CH3)(2)NH2]3BI2CL9 (DMACB)- PROTON SPIN RELAXATION STUDIES, Solid state communications, 100(7), 1996, pp. 519-523
Tris(dimethylammonium nona chloro dibismuthate), [(CH3]2NH2]3Bi2Cl9, f
amily has been investigated through proton magnetic resonance and rela
xation measurements as a function of temperature. Results indicate the
presence of two phase transitions at 152 and 78 K, accompanied by cha
nges in the reorientational dynamics of the cation groups. Above 152 K
, the [(CH3)(2)NH2](+) groups are undergoing isotropic reorientations
with dynamic inequivalence, while in contrast they exhibit two-fold ro
tations in the low temperature phase. The phase transition at 78 K see
ms to be associated with considerable change in the orientational orde
r of the molecular groups. Comparison is made with similar antimony (S
b) substituted compounds to discuss the microscopic effects of substit
ution of heavier bismuth (Bi) metal atom. Copyright (C) 1996 Published
by Elsevier Science Ltd