Infrared spectra of H2O+CO2 and H2+CO ices before and after proton irradiation showed that a major reaction in both mixtures was the interconversion of CO2?CO. Radiation synthesized organic compounds such as carbonic acid were identified in the H2O+CO2 ice. Different chemical pathways dominate in the H2O+CO ice in which formaldehyde, methanol, ethanol, and methane were identified. Sublimed material was also analyzed using a mass spectrometer. Implications of these results are discussed in references to comets. ¿ American Geophysical Union 1991