Electron Diffraction of Carbon Nanotubes

Carbon nanotubes formed in the absence of catalytic transition metals manifest two distinct forms of carbon structure. The exterior of the tubes is composed of stacks of graphite-like carbon with the c-axis oriented along the tube radius, so that one has arrays of benzenoid carbon arranged approximately in concentric cylinders. The interior of the tubes is composed of graphite-like crystallites of random orientation with respect to the tube axis.