Carbon Nanotubes
Carbon nanotubes represent another allotrope of carbon. Like the fullrenes, carbon nanotubes are constructed from sp²-hybridized carbon atoms and each is therefore connected to three others. Carbon nanotubes, however, contain only six-membered rings. These rings may have a variety of configurations, depending upon their oroentations. Two possibilities are the armchair and zig-zag configurations, represented with the models below.