ABSTRACT
CXF is synthesized mainly at room temperature in the presence of fluorides such as HF, IF5, WF6, SbF5, AgF, LiF, and so on. It seems difficult to yield Q F by exposing graphite to "pure fluorine gas” because the fluorine atom, which has limited polarizability, is strongly adsorbed on a graphite surface, forming no mobile charge transfer complex in the absence of fluoride. It is experimentally difficult to make such a reaction system (i.e., a system consisting of graphite and pure fluorine gas without any HF). In general, water molecules are adsorbed on the internal wall of a reactor and pipelines even under high vacuum. When fluorine gas is introduced into the reactor, adsorbed water molecules react with fluorine gas, producing a trace of HF (usually 0.1 to 0.4%, detected by an IR spectrum). Fluorine gas in a cylinder sometimes contains a small amount of HF. HF and/or another fluoride coexisting in the reaction system form a charge transfer complex, C*+ MFy+1? around the surface area of graphite, and then the intercalated fluorine atoms diffuse into the graphite gallery by means of a con centration gradient.
