Optimized geometries and C-13 NMR chemical shifts of fullerene C-82 have been calculated by density functional theory at the B3LYP/6-31G* level for all isolated-pentagon-rule (IPR) isomers with nonvanishing HOMO-LOMO gap (isomers 1, 2, 3, 4, 5, and 6). The calculated C-13 NMR spectrum of isomer 3 agrees well with the experimental spectrum of the C-2 isomer, while the predicted spectra of isomers 1 and 5 differ significantly from experiment. Thus, the observed isomer is unambiguously assigned to C-82:3 isomer for the first time. Both the energetic and NMR properties show that isomers 2 and 4 might be observable.