Structural characterization of Y@C82

The cation and anion of Y@C82 were prepared by controlled potential electrolysis, and their stabilities were investigated by spectroscopic methods. The anion is found to be much more stable than the cation under an air atmosphere. The cage structure of Y@C82 was determined by observing the 13C NMR spectrum of the stable diamagnetic anion. It is confirmed that Y@C82 has C2v symmetry.