The two isomeric compounds, octadecylfumaric acid and octadecylmaleic acid (C1 8H3 7OCOCH= CHCOOH) have been synthesized, and Langmuir–Blodgett films of their cadmium salts have been studied by means of transmission and grazing incidence reflection infrared spectroscopy. These measurements provided information about the orientation of molecular segments relative to the substrate surface as well as about the lateral packing ...