The internal motion of metal atoms in the endohedral fullerenes

Sc-45-NMR technique was applied to the chromatographically separated two isomers of Sc2C84 in solution. The results show that in one isomer two scandium ions are magnetically equivalent over the temperature range of 238 - 433 K, whereas in the second isomer two scandium ions are inequivalent below 383 K, each of which has a different chemical shift in the spectrum. Above 383 K coalescence occurs in the spectrum, indicating that these two scandium ions become equivalent due to the internal motion of them inside the fullerene cage.