Abstract: The thermal stability and the phase transition in the (n-C_nH_2ⁿ+1NH₂)₃ZnCl₄ (n = 9～12)have been studied by DSC and TG techniques. The thermal stability and the activation ene-rgies for the first decomposition step are inderendent of the hydrocarbon chain lenth. Allcompounds showed a solid-solid transition at 288～370K. The number of the phase transitionpeaks presents an odd-even effect. The total transition erithalpies and entropies increase withthe number of carbon atom in chains. The peak temperature of the main transition riseswith the increase of the chain length. The main phase transition has been assigned to thestructural transition of chains.

Key words: phase transition, bis(n-alkylammonium)tetrachlornzincate, melecular conformation