An sp-hybridized molecular carbon allotrope, cyclo[18]carbon

Carbon allotropes built from rings of two-coordinate atoms, known as cyclo[ n ]carbons, have fascinated chemists for many years, but until now they could not be isolated or structurally characterized because of their high reactivity. We generated cyclo[18]carbon (C 18 ) using atom manipulation on bilayer NaCl on Cu(111) at 5 kelvin by eliminating carbon monoxide from a cyclocarbon oxide molecule, C 24 O 6 . Characterization of cyclo[18]carbon by high-resolution atomic force microscopy revealed a polyynic structure with defined positions of alternating triple and single bonds. The high reactivity of cyclocarbon and cyclocarbon oxides allows covalent coupling between molecules to be induced by atom manipulation,…

• NS
  National Science Foundation
• LT
  Leverhulme Trust

  Award: RPG-2017-032
• SN
  Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung

  Awards: 177829, P300P2-177829, P300P2
• ER
  European Research Council

  Awards: 320969, 682144