Capacitance-potential curves of unusual form were obtained during the adsorption of triphenylbismouth and triphenylantimony at mercury electrodes from N-methylformamide,N,N-dimethylformamide dimethyl sulfoxide, propylene carbonate, and methanol solutions. Most of these systems present nonadsorption-desorption capacitance peaks at intermediate negative potentials. The nature of those peaks was investigated by phase-selective ac (alternating current) polarographic measurements at the dropping and hanging Hg electrodes. The application of phenomenological criteria relative to the form of the curves of the electrode charge density and the surface pressure against potential and calculation of the projection area of the adsorbate molecules on the electrode surface make it possible to identify the observed effect with the reorientation of triphenylbismouth and triphenylantimony.