Abstract
<jats:p> Möbius topology has long been explored in molecular systems but remains elusive in sp-hybridized carbon rings. Here, we report on-surface synthesis and characterization of a cyclo[9]carbon (C <jats:sub>9</jats:sub> ) that displays either Möbius or Hückel orbitals depending on the adsorption sites of substrate NaCl lattice. Bond-resolved AFM imaging and density functional theory calculations reveal that its nonplanar configuration (on a Cl-top site) is the ground state, and moreover, STM imaging combined with Dyson orbital analysis provides real-space visualization of the twisted orbital distribution. More importantly, tight-binding calculations on twisting angles of each p orbitals demonstrate a cumulative angle of 180° going around the cycle, confirming that the nonplanar C <jats:sub>9</jats:sub> adopts a Möbius orbital topology. In addition, the planar C <jats:sub>9</jats:sub> (on a Na-top site) exhibits the conventional Hückel orbitals. These findings present the first experimentally realized intrinsic Möbius cyclocarbon <jats:bold>.</jats:bold> </jats:p>