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Electron diffraction patterns of the fullerene C(60) in the gaseous state have been obtained by volatilizing it from a newly designed oven-nozzle at 730 degrees C. The many peaks of the experimental radial distribution curve calculated from the scattered intensity are completely consistent with icosahedral symmetry for the free molecule. On the basis of this symmetry assumption, least-squares refinement of a model incorporating all possible interatomic distances led to the values r(g)(C(1)-C(2)) = 1.458(6) angstroms (A) for the thermal average bond length within the five-member ring (that is, for the bond fusing five- and six-member rings) and r(g)(C(1)-C(6)) = 1.401(10) A for that connecting five-member rings (the bond fusing six-member rings). The weighted average of the two bond lengths and the difference between them are the values 1.439(2) A and 0.057(6) A, respectively. The diameter of the icosahedral sphere is 7.113(10) A. The uncertainties in parentheses are estimated 2sigma values.

The unfavorable D3h isomer of the C78 fullerene cage is present in Sc3N@C78, an endohedral fullerene which has been prepared by the trimetallic nitride template process. The crystal structure of the fullerene–porphyrin adduct Sc3N@C78⋅[Co(oep)]⋅1.5 C6H6⋅0.3 CHCl3 (oep=octaethylporphyrin) shows that the scandium atoms are located over the centers of the [6,6] ring junctions of pyracylene patches on the inner surface of the fullerene (see picture).

The pure I(h) isomer of Sc3N@C80 was allowed to react with N-triphenylmethyl-5-oxazolidinone via the corresponding azomethine ylide. The reaction results in the formation of two monoadducts; one (1b) is the kinetic product, and the other (1a) is thermodynamically more stable. Small amounts of the bisadducts were also formed. The structure of the thermodynamic monoadduct 1a was shown conclusively by NMR spectroscopy and X-ray crystallography to result from addition across the 5,6-ring junction. The kinetic product 1b was demonstrated to be the 6,6-ring juncture adduct on the basis of NMR experiments and X-ray crystallography. In refluxing chlorobenzene pure 1b was converted to the more thermodynamically stable 1a isomer. These N-tritylpyrrolidino derivatives are potentially useful precursor compounds for further derivatization for various applications.