Coaxial carbon nanotube. Computer illustration showing the molecular structure of one carbon nanotube inside another, known as a coaxial nanotube. Carbon nanotubes are cylindrical carbon molecules used in nanotechnology, electronics and materials science and technology. They are often used in electronics due to their high thermal conductivity and practical electrical properties, and are also added to various structural materials due to their high atomic strength. Coaxial carbon nanotubes are being developed for uses including anything from springs, to ratchet wheels and nano-bearings.