Superstrong Carbon Chains

One-dimensional strings of carbon atoms should be stronger than any known material, according to a theoretical study (ACS Nano 2013, DOI: 10.1021/nn404177r). The carbon allotrope, called carbyne, consists of chains of carbon atoms linked by alternating single and triple bonds. Researchers have previously synthesized polyyne chains of up to 44 atoms in length. Longer chains, as yet unsynthesized, would enable experimental verification of these predictions. Rice University chemist Boris I. Yakobson and colleagues calculated carbyne’s tensile strength by examining what happens when the distance between two carbon atoms increases, as would happen if a chain were stretched. The chemists also calculated how much force it could endure before becoming unstable. From those calculations, they predict that the tensile stiffness of carbyne should be twice that of graphene and carbon nanotubes. They also predict that carbyne could have novel electrical and magnetic properties. For example, twisting the carbon chain 90º from its normal state would transform it into a magnetic semiconductor, which could be useful in digital memory devices.