Carbon fulleroids

The electronic structure of the hypothetical fulleroids also parallels that of the fullerenes in several significant respects. Properly closed n shells are found within the Hiickel approximation only for isolated p-gon isomers, and then only when the structure is either (a) leapfrogged from a smaller fulleroid of the same symmetry, or (b) a p-fold analogue of one of the fullerene carbon cylinder series (Fowler 1990). D1(l C84 is the smallest fulleroid with a properly closed shell (figure 3). 

The regiochemistry of the addition reactions is governed by the minimization of the 5,6-double bonds within the fullerene skeleton. Therefore, any 1,2-ad-dition reactions produce ring-closed 6,6-adducts having two sp3 carbon atoms on the fullerene framework. However, sometimes ring-opened 6,5-adducts (fulleroids) are formed, keeping all fullerene carbon atoms sp2 hybridized. 

NEW ALLOTROPES OF CARBON GRAPHITE INTERCALATION COMPOUNDS, FULLERENES, FULLEROIDS, CARBON NANOTUBES, PEAPODS, AND GRAPHENE... 

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