Benzene-derived ​carbon nanothreads

Journal name:
Nature Materials
Year published:
Published online

Low-dimensional ​carbon nanomaterials such as fullerenes, nanotubes, graphene and diamondoids have extraordinary physical and chemical properties1, 2. Compression-induced polymerization of aromatic molecules could provide a viable synthetic route to ordered ​carbon nanomaterials3, 4, but despite almost a century of study5, 6, 7, 8, 9 this approach has produced only amorphous products10, 11, 12, 13, 14. Here we report recovery to ambient pressure of macroscopic quantities of a crystalline one- dimensional sp3carbon nanomaterial formed by high-pressure solid-state reaction of ​benzene. X-ray and neutron diffraction, Raman spectroscopy, solid-state NMR, transmission electron microscopy and first-principles calculations reveal close- packed bundles of subnanometre-diameter sp3-bonded ​carbon threads capped with hydrogen, crystalline in two dimensions and short-range ordered in the third. These nanothreads promise extraordinary properties such as strength and stiffness higher than that of sp2carbon nanotubes or conven tional high-strength polymers15. They may be the first member of a new class of ordered sp3 nanomaterials synthesized by kinetic control of high-pressure solid-state reactions.

At a glance


  1. Bright-field TEM micrographs and X-ray scattering of sp3 nanothreads.
    Figure 1: Bright-field TEM micrographs and X-ray scattering of sp3 nanothreads.

    a, TEM micrograph showing striations spaced 6.4 Å apart extending for tens of nanometres; this spacing is consistent with that obtained from X-ray and neutron diffraction analyses and crystal structure modelling. The line profile (bottom) along the marked path has 2 nm grid spacing. b, The same sample after sonication in ​pentane, which disrupts the lattice. Isolated nanothreads can be seen projecting out near the edge of the sample. Their curvature is consistent with the morphology predicted for isolated nanothreads by modelling (Fig. 3). c, Bragg peaks in the total X-ray scattering structure function are indexed to a 2D hexagonal lattice (a = 6.47 Å) as marked by vertical dashed lines. The relative suppression of the higher Q Bragg intensities is consistent with the structure factor of hexagonally close-packed tubes of electronic density. The broad background is attributed to disorder along the axis of the nanothreads. The inset shows the reduced PDF obtained by Fourier transforming S(Q), revealing crystalline domains larger than 15 nm.

  2. Experimental and modelled PDFs G(r).
    Figure 2: Experimental and modelled PDFs G(r).

    Experimental distribution functions (solid lines) were acquired with both neutron and high-energy X-ray diffraction. Modelled functions (dashed lines) are derived from a lattice of close-packed disordered sp3 nanothreads (Supplementary Information) with random axial shifts that average out most inter-thread correlations. Thin grey curves show the partial PDFs for the first few neighbours of each pair type (scaled down by a factor of two for clarity). The structural model agrees well with the experimental curve out to at least the third neighbour shell.

  3. Atomistic models and Stone–Wales transformation.
    Figure 3: Atomistic models and Stone–Wales transformation.

    Two Stone–Wales transformations of the off-axial bonds interconvert the (3,0) tube and polymer I, showing that these two structures are members of a single structural class. A disordered admixture of Stone–Wales transformations (with periodic axial boundary conditions) yields the structure shown on the right; this nanothread was also used as the basis for calculating the PDF.

  4. Visible Raman spectra in the C–C mode ‘fingerprint’ region of 12C and 13C nanothreads collected with 633 nm excitation.
    Figure 4: Visible Raman spectra in the C–C mode ‘fingerprint’ region of 12C and 13C nanothreads collected with 633 nm excitation.

    The spectral positions and isotopic shifts (13C/12C mass ratio square root ≃ 0.961) of these modes identify them as arising from motion of coupled C–C single bonds. The insets show the radial breathing and flexure modes for a (3,0) nanotube. The asterisk marks a peak associated with the substrate used for the 12C nanothreads.


  1. Dahl, J. E., Liu, S. G. & Carlson, R. M. K. Isolation and structure of higher diamondoids, nanometer-sized diamond molecules. Science 299, 9699 (2003).
  2. Jariwala, D., Sangwan, V. K., Lauhon, L. J., Marks, T. J. & Hersam, M. C. Carbon nanomaterials for electronics, optoelectronics, photovoltaics, and sensing. Chem. Soc. Rev. 42, 28242860 (2013).
  3. Wen, X. D., Hoffmann, R. & Ashcroft, N. W. Benzene under high pressure: A story of molecular crystals transforming to saturated networks, with a possible intermediate metallic phase. J. Am. Chem. Soc. 133, 90239035 (2011).
  4. He, C. Y., Sun, L. Z., Zhang, C. X. & Zhong, J. X. Low energy three-dimensional hydrocarbon crystal from cold compression of benzene. J. Phys. Condens. Matter 25, 205403 (2013).
  5. Thiery, M. M. & Leger, J. M. High-pressure solid-phases of benzene. 1. Raman and x-ray studies of C6H6 at 294-K up to 25-GPa. J. Chem. Phys. 89, 42554271 (1988).
  6. Ciabini, L. et al. Triggering dynamics of the high-pressure benzene amorphization. Nature Mater. 6, 3943 (2007).
  7. Bridgman, P. W. Change of phase under pressure. I. The phase diagram of eleven substances with especial reference to the melting curve. Phys. Rev. 3, 153203 (1914).
  8. Block, S., Weir, C. E. & Piermarini, G. J. Polymorphism in benzene, naphthalene, and anthracene at high pressure. Science 169, 586587 (1970).
  9. Piermarini, G. J., Mighell, A. D., Weir, C. E. & Block, S. Crystal structure of benzene-2 at 25-kilobars. Science 165, 12501255 (1969).
  10. Schettino, V. & Bini, R. Constraining molecules at the closest approach: Chemistry at high pressure. Chem. Soc. Rev. 36, 869880 (2007).
  11. Ciabini, L., Santoro, M., Bini, R. & Schettino, V. High pressure reactivity of solid benzene probed by infrared spectroscopy. J. Chem. Phys. 116, 29282935 (2002).
  12. Citroni, M., Bini, R., Foggi, P. & Schettino, V. Role of excited electronic states in the high-pressure amorphization of benzene. Proc. Natl Acad. Sci. USA 105, 76587663 (2008).
  13. Pruzan, P. et al. Transformation of benzene to a polymer after static pressurization to 30 GPa. J. Chem. Phys. 92, 69106915 (1990).
  14. Ceppatelli, M., Santoro, M., Bini, R. & Schettino, V. High pressure reactivity of solid furan probed by infrared and Raman spectroscopy. J. Chem. Phys. 118, 14991506 (2003).
  15. Stojkovic, D., Zhang, P. H. & Crespi, V. H. Smallest nanotube: Breaking the symmetry of sp3 bonds in tubular geometries. Phys. Rev. Lett. 87, 122502 (2001).
  16. Bini, R., Ceppatelli, M., Citroni, M. & Schettino, V. From simple to complex and backwards. Chemical reactions under very high pressure. Chem. Phys. 398, 262268 (2012).
  17. Chelazzi, D., Ceppatelli, M., Santoro, M., Bini, R. & Schettino, V. High-pressure synthesis of crystalline polyethylene using optical catalysis. Nature Mater. 3, 470475 (2004).
  18. Aoki, K., Kakudate, Y., Yoshida, M., Usuba, S. & Fujiwara, S. Solid state polymerization of cyanoacetylene into conjugated linear chains under pressure. J. Chem. Phys. 91, 778782 (1989).
  19. Kovacic, P. & Koch, F. W. Polymerization of benzene to p-polyphenyl by ferric chloride. J. Org. Chem. 28, 18641867 (1963).
  20. Thess, A. et al. Crystalline ropes of metallic carbon nanotubes. Science 273, 483487 (1996).
  21. Egami, T. & Billinge, S. J. L. Underneath the Bragg Peaks: Structural Analysis of Complex Materials 2nd edn, Vol. 16 (Pergamon Materials Series, Pergamon-Elsevier Science, 2012).
  22. Barua, S. R. et al. Polytwistane. Chem. Eur. J. 20, 16381645 (2014).
  23. Robertson, J. Photoluminescence mechanism in amorphous hydrogenated carbon. Diam. Relat. Mater. 5, 457460 (1996).
  24. Schluter, A. D. Ladder polymers-the new generation. Adv. Mater. 3, 282291 (1991).
  25. Li, Z. Q., Lu, C. J., Xia, Z. P., Zhou, Y. & Luo, Z. X-ray diffraction patterns of graphite and turbostratic carbon. Carbon 45, 16861695 (2007).
  26. Ciabini, L., Santoro, M., Bini, R. & Schettino, V. High pressure photoinduced ring opening of benzene. Phys. Rev. Lett. 88, 085505 (2002).
  27. Schettino, V., Bini, R., Ceppatelli, M., Ciabini, L. & Citroni, M. Chemical reactions at very high pressure. Adv. Chem. Phys. 131, 105242 (2005).
  28. Klotz, S., Hamel, G. & Frelat, J. A new type of compact large-capacity press for neutron and X-ray scattering. High Press. Res. 24, 219223 (2004).
  29. Fang, J., Bull, C. L., Loveday, J. S., Nelmes, R. J. & Kamenev, K. V. Strength analysis and optimisation of double-toroidal anvils for high-pressure research. Rev. Sci. Instrum. 83, 093902 (2012).

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  1. Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA

    • Thomas C. Fitzgibbons,
    • Vincent H. Crespi &
    • John V. Badding
  2. Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA

    • Thomas C. Fitzgibbons,
    • En-shi Xu,
    • Vincent H. Crespi &
    • John V. Badding
  3. Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015, USA

    • Malcolm Guthrie &
    • George D. Cody
  4. Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, USA

    • En-shi Xu &
    • Vincent H. Crespi
  5. Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA

    • Vincent H. Crespi &
    • Nasim Alem
  6. Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA

    • Stephen K. Davidowski


T.C.F., M.G. and J.V.B. conceived the project. T.C.F. developed synthesis procedures. T.C.F. and M.G. collected neutron and X-ray diffraction data. T.C.F., M.G., E-s.X., V.H.C. and J.V.B. analysed the diffraction data and PDFs. S.K.D. and G.D.C. collected and analysed SSNMR spectra. T.C.F. collected TEM data under the guidance of N.A. E-s.X. and V.H.C. performed first-principles calculations. T.C.F., M.G., E-s.X., V.H.C. and J.V.B. wrote the manuscript. All authors discussed it.

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