MONOLAYERS OF POLAR METHANE DERIVATIVES PHYSISORBED ON GRAPHITE

Physisorbed monolayers are the closest approximation ro two-dimensional arrangements of matter. The halomethanes are the first larger class of polar molecules which have been studied in such arrangements. Experimental information, mainly from diffraction and heat capacity studies, is available on the adsorbates CH3F, CH3Cl, CH3Br, CH3I, CF3H, CF3Cl, CF3Br, CHF2Cl, and CF2Cl2, physisorbed on graphite (001). The structures, phase diagrams and phase transitions are reviewed. Complementary information on the non-polar reference systems CH4, CF4 and CCl4 is included.