Motion of Scandium Ions in Sc2C84 Observed by 45Sc Solution NMR

We have used 45 Sc solution NMR spectroscopy to show for the first time the internal motion of the scandium ions in two Sc 2 C 84 isomers. In one isomer the two scandium ions are equivalent over the temperature range 238−433 K, whereas in the second isomer there are two inequivalent scandium ions below 383 K. At 383 K coalescence occurs, and above that temperature the scandium ions become equivalent. The processes are reversible, and we believe this is the first time such phenomena have been observed.