The behavior of 5-nitro-1,10-phenanthroline (I) at a hanging Hg-drop electrode (HMDE) was investigated by linear sweep adsorption voltammetry. At a potential of -0.1 to 0.2 V (vs. SCE), the I can be adsorbed on the surface of the HMDE very well. When the potential is scanned in the neg. direction, a peak is obtained. The peak potential is -0.38 V for a scanning rate of 100 mV/s. The experimental data for the degree of adsorption and peak current agree with the theor. prediction. The reduction of I at the HMDE is irreversible. The no. of electrons transferred in the overall reaction is 4. The no. of transferred electrons and symmetry coefficient in the rate-detg. step are 3 and 0.42, resp.

Key words: NITRO COMPOUNDS, VOLTAMMETRY, ADSORPTION, PHENANTHROLINE, VOLTAMPERE CHARACTERISTIC