Sc-2@C-76 was for the first time isolated and characterized spectroscopically. It is suggested from the C-13 NMR spectroscopy (C-13 NMR pattern: 38 x 2) that this metallofullerene has a C symmetry, in contrast to the D-2 symmetry of an empty C-76 fullerene cage. Ab initio calculations were performed to explore the symmetry changes for C76 (from D-2 to C) induced by the endohedral scandium ions. It is found that the scandium ions are located at two of the three main C axes of C-76(D-2). The two isomers Sc-2@C-76(D2-x) (Sc-2 was put along the C-2x axis of C-76(D-2)) and Sc-2@C-76(D2-y) (Sc-2 was put along the C-2y axis of C-76(D-2)) are nearly iso-energetic in their optimised geometrical structures, and their energies are much lower than that of the third isomer Sc-2@C-76(D2-z) (Sc-2 was put along the C-2z axis of C-76(D-2)). Each of the two iso-energetic isomers, i.e., Sc-2@C-76(D2-x) and Sc-2@C-76(D2-y), contributes 19 NMR lines (C-13 NMR pattern: 19 x 4), so the mixture of them shows overall 38 NMR lines (C-13 NMR pattern: 38 x 2) for this metallofullerene. (C) 2002 Elsevier Science B.V. All rights reserved.