The long-sought small-bandgap endohedral fullerene Sc3N@C-82 with low kinetic stability has been successfully synthesized and isolated for the first time, for which the molecular structure has been unambiguously determined as Sc3N@C-82-C-2v(39718) by single crystal X-ray diffraction. The C-82-C-2v(39718) (or labeled as C-82-C-2v(9) according to the conventional numbering of the isolated pentagon rule (IPR) isomers based on the Fowler-Monolopoulos spiral algorithm) isomeric cage of Sc3N@C-82 agrees well with its most stable isomer previously predicted by DFT computations and is dramatically different to those of the reported counterparts M3N@C-82-Cs(39663) (M = Gd, Y) based on a non-IPR C-82 isomer, revealing the strong dependence of the cage isomeric structure on the size of the encaged metal for C-82-based metal nitride clusterfullerenes (NCFs).