The joint vibrational and structural study of n-decylammonium chloride results in a fair description of the solid phases and their interconversions during the thermotropic phase transitions. Phase i (stable below 3 12 K) crystallizes as a well-ordered, interdigitated layer structure, whereas phases CY (stable above 318 K),/3 (stable between 318 and 316 K), b (stable between 316 and 302 K), and t (metastable below 302 K) represent intermediate ...