ABSTRACT
The in-plane structure of Q F depends strongly on the fluorine intercalation rate (i.e., synthetic methods). When intercalation rate is high, that is, anhydrous liquid HF or gaseous HF is used, intercalated fluorine atoms are randomly ori ented between carbon sheets at any stage. Only some diffraction lines originating from host graphite lattice are detected by x-ray or electron diffraction. As already mentioned, the fluorine intercalation rate is decreased with a decreasing amount of HF in a reaction system. When Q F is synthesized in the presence of AgF (HF < 0.01%) or in a fluorine atmosphere containing a small amount of SbF5 or WF6 (HF: 0.1 to 0.4%), stage 2 and 3 compounds show an in-plane super lattice belonging to a hexagonal system (a0 = 2ag) [10]. This was shown by Debye-Scherrer films and electron diffraction patterns of all the samples pre pared [10]. A typical example obtained by electron diffraction is shown in Fig. 1 1 , where very sharp diffraction spots are observed between the center and the diffraction spots originating from host graphite lattice [(100), (200), (300), (110), (220), and (210) lines]. Therefore, the diffraction spots from graphite lattice are indexed as (200), (400), (600), (220), (440), and (420) lines in the superlattice, and the lattice parameter, a0, is double that of graphite, 2ag.
