RAMAN-SPECTROSCOPIC STUDY OF CRYSTAL PHAS E-TRANSITION IN BIS(N-UNDECYLAMMONIUM) TETRACHLOROZINCATE

The solid-solid phase transition of [n-C11H23NH3]2ZnCl4 Complex have b een studied by Raman spectroscopy. The results show that the occurence of the structural phase transitions mainly related to the change of p acking structure and molecular conformation of chains. The phase at T( c1) = 25-degrees-C is due to the change of packing state and conformat ion of chains from order to partial disorder. In the intermediate temp erature phase, the chains contain partial gauche isomers. The phase tr ansition at Tc2 = 87-degrees-C arises from change to the all disorder of the alkyl chains. The high temperature phase leads to a ''chain mel ting''.