Carbon-atom chain formation in the core of nanotubes

Here we report the observation of a linear carbon-atom chain, synthesized using an are discharge from a graphite double anode. We use high-resolution TEM to evidence the formation of a carbon-atom chain along the axis of a needlelike structure consisting of concentric cylindrical graphitic shells. The atomic chain in the core of the innermost cylinder, by calculations on the basis of van der Waals interactions, demonstrates an extremely high thermal stability (up to 4200 K) and exhibits high mechanical strains.