Solid-state 19F and 13C NMR of room temperature fluorinated graphite and samples thermally treated under fluorine:: Low-field and high-resolution studies

Room temperature graphite fluorides consisting of raw material and samples post-treated in pure fluorine atmosphere in the temperature range 100-500 degrees C have been studied by solid-state NMR. several NMR approaches have been used, both high and low-field F-19, F-19 MAS and C-13 MAS with F-19 to C-13 cross polarization. The modifications, in the graphitic lattice. of the catalytic iodine fluorides products have been examined. A transformation of the C-F bond character from semi-ionic to covalent has been found to occur at a post-treatment temperature close to 400 degrees C. It is shown that covalency increases with temperature. (c) 2005 Elsevier Inc. All rights reserved.