Comparison of the oxidizing ability of graphite and fullerite Original Research Article

This study is devoted to the comparison of the oxidizing ability of graphite and fullerite towards the three heavy alkali metals. These elements are able to intercalate very easily into graphite and fullerite, leading to various binary compounds. In the case of graphite, that is 2D host material, the alkali metal atoms intercalate in the bidimensional van der Waalsʹs gap. These latter can be systematically occupied (stage 1 compound) or not (stages 2, 3…); the alkali metal concentration decreases from the first to the higher stages. On the other hand, C60 fullerite is OD host material, and the alkali metal atoms intercalate into the octahedral and tetrahedral sites of the fullerite classical FCC structure. According to the cases, these interstitial sites can be more or less occupied, leading to several well defined phases. For all these compounds, a charge transfer occurs between carbon host material and alkali metal, that greatly reduces graphite and fullerite, so that the binary compounds are considered as salts, that is, graphitides and fullendes, respectively. We have shown that fullerite is much more oxidizing than graphite. This latter indeed is strongly (in cesium) or even completely (in rubidium and potassium) striped of its alkali atoms by fullerite. In other words, graphitides are partly or entirely oxidized by fullerite.