A carbon nanotube is an allotrope of carbon that is shaped like a tube of carbon atoms. Carbon nanotubes are very tough and hard to break, but still relatively light. Some are very long. Because of their high strength, carbon nanotubes may one day be used for bulletproof armour and other uses needing hard, lightweight materials.

A nanotube is a nanometer-scale hollow tube-like structure.. Kinds of nanotubes. BCN nanotube, composed of comparable amounts of boron, carbon, and nitrogen atoms; Boron nitride nanotube, a polymorph of boron nitride; Carbon nanotube, includes general nanotube terminology and diagrams; DNA nanotube, a two-dimensional lattice which curves back upon itself, somewhat …

Carbon nanobuds are a newly created material combining two previously discovered allotropes of carbon; carbon nanotubes and fullerenes. In this new material fullerene-like "buds" are covalently bonded to the outer sidewalls of the underlying carbon nanotube. This hybrid material has useful properties of both fullerenes and carbon nanotubes.

Legăturile carbon-carbon sunt destul de puternice și anormal de stabile. Această caracteristică este importantă deoarece permite carbonului să formeze un număr extrem de mare de compuși; de fapt, există mai mulți compuși chimici care conțin carbon decât toți compușii celorlalte elemente chimice la un loc.