They apparently have the structure of a hollow spheroidal cage with a surface network of carbon atoms connected in hexagonal and pentagonal rings.
Carbon nanotubes are similar to fullerenes, except their shape is tubular.
There have been rapid developments in understanding the chemistry and physics of carbon nanotubes, and there is much excitement in both the chemistry and physics communities concerning possible applications of these unique structures. Carbon nanotubes exhibit unique quantum wire properties that derive from the nanometer diameters of the tubes in combination with the special electronic structure of graphite. Bohm studies, in which the nanotube resistance is modulated by a magnetic field along the tube axis. As a result, no heat is dissipated in the tubes, and very high current densities can be obtained without destroying the tube. These structures are extremely versatile.