Magnetic properties of endohedral fullerene complexes

The type as well as the electronic state of endohedral fullerene complexes have been determined by the simultaneous application of mass spectrometry, ESR spectroscopy and magnetic measurements. Endohedral fullerenes containing the rare earth metals Eu, Gd, Tm and Yb give mass spectra corresponding to singly and double filled cages. But the expected ESR spectra were not found, Magnetizati-on-vs.-temperature/field measurements showed the Gd to be trivalent, whereas the Eu is divalent in the endohedral fullerenes.