Orientational Disorder in Solvent-Free Solid C<sub>70</sub>
VAUGHAN, GAVIN B. M.; HEIEY, PAUL A.; LUZZI, DAVID E.; RICKETTS-FOOT, DEBORAH A.; MCGHIE, ANDREW R.; FISCHER, JOHN E.; HUI, YIU-WING; SMITH, ALLAN L.; COX, DAVID E.; ROMANOW, WILLIAM J.; ALLEN, BRENT H.; COUSTEL, NNICOLE; MCCAULEY, JOHN P.; SMITH, AMOS B.; Laboratory for Research on the Structure of Matter and Physics Department, University of Pennsylvania, Philadelphia, PA 19104; N. Coustel, Laboratory for Research on the Structure of Matter and Materials Science and Engineering Department, University of Pennsylvania, Philadelphia, PA 19104; Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104; Chemistry Department, Drexel University, Philadelphia, PA 19104; Physics Department, Brookhaven National Laboratory, Upton, NY 11973; Laboratory for Research on the Structure of Matter and Chemistry Department, University of Pennsylvania, Philadelphia, PA 19104
Журнал:
Science
Дата:
1991
Аннотация:
The high-temperature structure of solvent-free C<sub>70</sub> has been determined with high-resolution x-ray powder difraction and electron microscopy. Samples crystallized from solution form hexagonal close-packed crystals that retain an appreciable amount of residual toluene, even after prolonged heating. Samples prepared by sublimation, which contain no detectable solvent, are primarily face-centered cubic with some admixture of a hexagonal phase. The relative volume of the hexagonal phase can be further reduced by annealing. The structures of both phases are described by a model of complete orientational disorder. The cubic phase contains an appreciable density of stacking faults along the [111] direction.
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