Two successive phase transitions in bis-n-dodecylammonim hexachlorostannate, (n-C12H2SNH3)(2)SnCl6, were studied by means of H-1 NMR. From the temperature dependent dipolar splitting, the low and the high temperature transition were attributed to an order-disorder transition and a conformational transition of the rigid hydrocarbon chain, respectively. The spinlattice relaxation rate in the low and the intermediate temperature phase was well fitted with four types of molecular motions, and the ammonium group was revealed to dictate the order-disorder transition temperature. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 20]
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