Isocyanides (C=N-R) adsorbed from 1,2-dichloroethane(DCE) solution on powdered gold were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Concentration measurements showed that adsorption equilibrium constants decrease in the order : CNPh > CNCH2C(O)OEt > 4-CNC6H4-NO2 > CNBu(n). This is a different order than that (CNBu(t) similar to CNBu(n) > CNCH2C(O)OEt > CNPh > 4-CNC6H4-NO2) observed for the binding of isocyanides in the complex AuCl(C=N-R); this latter order indicates that the isocyanides with the highest sigma-donor ability bind the most strongly. At saturation coverage, the number of moles of adsorbed C=N-R per gram of Au decreases as the size of the R group increases : CNBu(n) > CN(c-C6H11) > CNBu(t) > 2,4,6-CNC6H2(But)(3). For the least bulky isocyanide (CNBu(n)), the ratio of CNBu(n) molecules to surface Au atoms is approximately 1/3.9. From calculated cross-sectional areas of the R groups in the isocyanides, it is estimated that two-thirds of the surface area is covered at saturation coverage for all of the isocyanides. Gold powder that is surface-oxidized by Cl-2 adsorbs CNBu(n) but AuCl-(CNBu(n)) desorbs into the DCE solution.