A Class of Carbon Allotropes: One-Dimensional Interlocked Carbon Chains

Carbon allotropes such as diamond and graphene have long driven material innovations; nevertheless, the quest for novel carbon architectures remains unrelenting, driven both by curiosity and the tantalizing prospect of tailoring materials with atomic precision to address global challenges. Here, a class of one-dimensional (1D) carbon allotropes with interlocked geometries were proposed theoretically, in which carbon atoms form multicenter σ bonds—a bonding feature absent in all known carbon allotropes. Molecular dynamics simulations demonstrated that certain stability exists for these carbon chains. Furthermore, the 1D interlocked carbon chains possess a band gap in the range of 4.00–4.20 eV, bridging the gap between polyyne-type carbon chain and diamond. The unconventional bonding mechanism enriches carbon chemistry while challenging traditional carbon bonding theories. Beyond the carbon allotrope family, this work opens avenues for discovering allotropes of other group 14 elements.