A NEW STAGE-2 GRAPHITE-INTERCALATION COMPOUND - C2F WITH NESTLED FLUORINE-ATOMS

A new stage-2 graphite intercalation compound, C2F, with nestled fluor ine atoms, has been synthesized by flowing fluorine gas in anhydrous l iquid HF at - 76-degrees-C. This compound can be prepared only from su ch a well-defined host as highly oriented pyrolytic graphite (HOPG), a nd has a large I(c) value of 11.14 angstrom with intercalated thicknes s, d(i) = 4.44 angstrom. XPS and IR spectroscopy have revealed the ion ic character of C-F bonding, and the electrical conductivity was found to be much higher than that of pristine graphite. Based on these expe rimental results, a structural model in which two nestled fluorine lay ers are superposed between two carbon sheets has been proposed. The ne stling effect well explains the high air stability of this compound.