CHEMICAL COMPOSITION AND CRYSTAL-STRUCTURE OF GRAPHITE FLUORIDE

The relation between the composition and crystal structure of graphite fluoride is studied. The formation of a new chemical compound, “polydicarbon monofluoride”, represented by the formula (C2F)n, was confirmed under relatively mild direct fluorination of graphite. The composition of nonstoichiometric graphite fluoride prepared at temperatures less than 600 °C is not homogeneous but a mixture of (CF)nand (C2F)n. The fluorination of graphite first leads to the formation of (CF)nin the very thin film of surface followed by the formation of (C2F)nand further fluorination again leads to the formation of (CF)n. The ratio (C2F)n/(CF)n, which is strongly dependent on the reaction temperature, decreases with increasing temperature. The composition of graphite fluoride with F/C ratio less than unity varies no longer even after the treatment at higher temperature in a fluorine atmosphere. The color of graphite fluoride does not depend on the composition but on the reaction and treatment temperature. The two-dimensional structure of (C2F)nis regarded as a monoclinic system. The lattice constants are a = 5.01 Å,b = 4.92 Å, and Γ = 120.6°. The stacking of the above layers is a turbostratic structure which consists of layers stacked randomly at the same distance of about 8.8 Å. © 1979, American Chemical Society. All rights reserved.