Cyclo[18]carbon, the Newest Member of the Family of Carbon Allotropes

Discovery of a new allotrope of carbon, especially one that exists as a molecular form, is an exceedingly rare find in science. In a recent issue of Science, Anderson, Gross, and coworkers reported the on-surface synthesis of cyclo[18] carbon and showed that the all-sp-hybridized ring possessed a polyynic topology.