Angewandte Chemie International Edition

Cover image for Vol. 56 Issue 44

Editor: Neville Compton; Editor Emeritus: Peter Gölitz

Online ISSN: 1521-3773

Associated Title(s): Angewandte Chemie, Chemistry - A European Journal, Chemistry – An Asian Journal, ChemistryOpen, ChemPhotoChem, ChemPlusChem, Zeitschrift für Chemie

Cover Picture

02/2001The cover picture shows a section of the electron charge density of the first metal carbide endohedral metallofullerene (Sc2C2)@C84 obtained from a synchrotron X-ray powder diffraction study by the maximum entropy method (MEM). The several density maxima, which correspond to scandium and carbon atoms, are clearly seen inside the C84 carbon cage. The MEM charge density distribution also reveals that the C84 cage has D2d symmetry (no. 23) and that the C2 axis is parallel to the <100> face-centered cubic (fcc) direction of the unit cell. As a consequence of the site symmetry being 4mm, the C2 axis of (Sc2C2)@C84 is oriented to six equivalent <100> directions and shows a merohedral disorder. The resultant Sc···Sc distances and C−C bond lengths of the Sc2C2 cluster are 0.429(2) and 0.142(6) nm, respectively. The observed C−C bond length is between that of a typical single and a double bond, and is very close to that of the C−C bond (0.143 nm) combining two pentagons in a C60 molecule. More about this fascinating structure can be found in the contribution by Shinohara and co-workers on p. 397 ff.

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