New cyclic carbon allotropes

Exploration of new all-carbon molecules and materials (allotropes) is fundamental for the understanding of chemical phenomena such as aromaticity and conjugation, but also for the development of new materials with e.g. superconducting properties for the future of a hightechnology society.

Question: Can we synthesize cyclic structures containing only carbon atoms, cyclo[n]carbon (n denotes the number of carbon atoms in the ring)? Can we use these cyclo[n]carbons to grow new types of well-defined single-walled carbon nano-tubes (SWCNTs)?