Fig. 1: Schematic illustrations of known or predicted carbon allotropes.
From: Synthesis of a magnetic π-extended carbon nanosolenoid with Riemann surfaces
a 2D extended graphene, the thinnest sp2 allotrope of carbon arranged in a honeycomb lattice. b 1D graphene nanoribbons with armchair edges (AGNRs) and zigzag edges (ZGNRs). c Examples of the predicted structure of helically twisted graphenes with Riemann surface. d (I) Design of the 3D fully π-extended curved single-stranded carbon nanosolenoids (CNS)25. (II) The atomic structure of CNS with side view by the DFT calculations. (III) Helical structure of CNS without the alkyl substituent groups. Burgers vector b parallel to the c-axis (purple). D, p, and γ are the outer diameter, pitch, and coil angle, respectively. (IV) Edges and helical core structures of CNS. Fig. 1c (left) adapted with permission from ref. 25 (copyright 2016 American Chemical Society), Fig. 1c (middle) adapted with permission from ref. 66 (copyright 2019 American Physical Society), and Fig. 1c (right) adapted with permission from ref. 67 (copyright 2018 American Chemical Society).
