NMR and NEXAFS Study of Various Graphite Fluorides.
Résumé
Graphite fluorides with different structural types (CyF)n (y = 2.5, 2, and 1) and room temperature graphite fluorides were studied by solid state NMR and NEXAFS. Data extracted from those two techniques are complementary, providing information about the C-F bonding and the hybridization character of the carbon atom valence states. The comparison of data obtained by different methods such as NMR, Raman, and X-ray absorption leads to similar conclusions regarding the chemical bonding in fluorographites. Several major configurations of fluorinated graphites are discussed, that is, planar sheets with mainly sp2 hybridization in room temperature graphite fluorides and corrugated sheets with sp3 hybridization in covalent high temperature graphite fluoride. Different references such as highly oriented pyrolytic graphite (HOPG), graphitized carbon nanodiscs (graph-CNDs) and nanodiamonds (NDs) have also been investigated for comparison.