Normal unenhanced Raman spectra (NURS) of low-polarizability CO molecules were observed for the first time on cobalt at R. T. and residual gas pressure. We assign five bands observed between 2030–2130 cm−1to linear chemisorbed CO species, while those observed between 1840–2010 cm−1have been ascribed to the 2-fold chemisorbed species. The three bands observed between 1740–1830 cm−1we believe are due to the 3-fold species. The corresponding fourteen Co-C stretches were observed and assigned. A model based upon electron backdonation is proposed for each of the three structures. NURS were also observed at R. T. for physisorbed CH4and assignments are made to the four frequencies of CH4.