Comparative NMR study of new carbon forms

• Published in: Carbon (New York) Vol. 34; no. 10; pp. 1287 - 1291
• Main Authors: Maniwa, Y., Sato, M., Kume, K., Kozlov, M.E., Tokumoto, M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1996; Elsevier Science
• Subjects: C 60; carbon nanotube; Condensed matter: structure, mechanical and thermal properties; diamond; Elemental solids; Exact sciences and technology; fullerenes; hard carbon; NMR; Physics; polymer; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; polymer; NMR; diamond; carbon nanotube; C 60; fullerenes; hard carbon; Temperature dependence; Cage compound; Diamonds; Hard materials; Nanostructures; Experimental study; Carbon; Nonmetals; Fullerenes; Carbon molecules; NMR spectra; Polymers; Comparative study; Atomic clusters; Crystal structure
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/0008-6223(96)00116-9

A comparative 13C-NMR study of several new phases of pressure/temperature-treated C 60, a bundle of carbon nanotubes, graphite and diamond was carried out in the 4–300 K temperature range. It was found that face-centered cubic and rhombohedral high-pressure phases of C 60 reveal very unusual NMR lines at 110 and 70 ppm, respectively, shifted from that of pristine C 60 (143 ppm). These lines disappear in a hard carbon phase prepared by compression of C 60 at more severe conditions. Comparison with NMR spectra of pristine C 60, diamond and graphite showed that the fullerenes acquire some partial sp 3 character when they are pressure-treated at 3–4.6 GPa and various temperatures (720 °C). However they are apparently not transformed into four-fold-coordinated diamond-like carbon clusters. NMR spectra of carbon nanotubes exhibited an anomalous shift which may be attributed to their cylindrical geometry.