The square-wave voltammetry of isolated isomers of C-84 is reported. Based on their relative abundance, the isomers are assumed to have D-2 and D-2d symmetry. The D-2 isomer has four reversible reductions at -0.65, -0.98, -1.34, and -1.75 V versus Fc/Fc(+) prior to electrolyte decomposition. This behavior is consistent with previous reports, and is similar to the voltammetry of C-60 and C-70 (e.g. sequential reductions spaced at slightly increasing intervals). The D-2d isomer has five reversible reductions at -0.46, -0.77, -1.58, -1.98, and -2.27 V versus Fc/Fc(+) prior to the onset of electrolyte decomposition. The large potential difference separating the second and third reductions of the D-2d isomer is an aspect of the voltammetry not reported when the D-2d isomer was analyzed as part of a mixture of C-84 isomers (P.L. Boulas, M.T. Jones, R.S. Ruoff et al., J. Phys. Chem. 100 (1996) 7573-7579). The large potential difference between the second and third reductions of the D-2d isomer of C-84 is similar to the voltammetric behavior of C-82.