An ultrathin carbon nanotube that is stable up to temperatures of 1,000 kelvin has been predicted by a team at the Autonomous University of Madrid. The structure resembles a double helix, with alternating single, double and triple carbon–carbon bonds.

Eduardo Menéndez-Proupin and his colleagues simulated the structure and described the spectral signatures that would enable scientists to identify it experimentally. The predicted molecule is just 0.32 nanometres in diameter. Standard nanotubes this thin have never been observed, because the carbon bonds in their six-atom rings have large distortions and become destabilized as the nanotubes get thinner. The carbon rings in the predicted molecule are larger than in standard nanotubes, and the bonds are arranged such that they are less strained.

Phys. Rev. Lett. 109, 105501 (2012)