In situ infrared reflection spectroscopy with electrochemical modulation has been used to investigate the structure of the double layer for the system polycrystalline gold/dimethylacetamide interface. The electrolyte was [Cr(C2H6SO)(6)](ClO4)(3). It has been found that the chromium complex accumulates in the double layer at potentials negative of the point of zero charge, replacing perchlorate anions and some solvent molecules. The spectroscopic data are used to discuss the orientation of the solvent in the inner pan of the double layer and accumulation of electrolyte ions in the diffuse part.