Graphite fluorides prepared at room temperature 1. Synthesis and characterization

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We have previously investigated the intercalation reaction of metallic or non-metallic fluorides MF n (IF 5, NbF 5, TaF 5, MoF 6, WF 6, ReF 6, BF 3, …) with graphite in a fluorine atmosphere, and no fluorination of the graphite lattice was detected. In this paper we show that if this process is carried out in the presence of HF at room temperature, partial fluorination of graphite occurs and first-stage graphite fluoride products of formula CF x M y (0.5 ⩽ x ⩽ 0.9, 0.06 ⩾ y ⩾ 0.02 and M is I, Cl, Br, Re, W, Mo or B) are obtained. The fluorine-richer products with x = 0.9 are obtained when the IF 7 or IF 5-F 2-HF system is used. X-ray diffraction and i.r. spectroscopy studies show that in these new compounds, the planarity of graphene layers is preserved and CF bonds are probably predominantly ionic in character. These results are different from those of (CF x ) n prepared at high temperatures (chair structure and covalent CF bonds).