Intercallation of alkalis in fullerite

Finally, we note that there is much interest in so-called nanotubes made of C atoms. These appear to be essentially elongated giant fullerenes [676]. 

As remarked in section 11.8, materials formed from fullerenes are of interest to develop as anodes for rocking chair batteries. We describe here some of the relevant properties, which depend not on endohedral capture, but rather on interstitial storage or reversible intercallation. 

The fullerenes are very stable, and can be formed into a solid called fullerite by a compact stacking of Ceo molecules which, for the phase of interest here, crystallises as a face-centred cubic structure of side 14.17 A. Two interstitial sites are available an octahedric site (one site per Ceo of radius 2.06A) and a tetrahedral site (two sites per Ceo of radius 1.12A [677]). Pure fullerite is actually an insulator states near the gap are primarily formed from tt orbitals of the molecule. Since Ceo has a very 

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