Deposition of ozone with either 2-iodopropane, pentafluoroiodoethane, 1,1,1-trifluoroiodoethane, 1,1,2,2-tetrafluoroiadoethane, or 1,1,1,2-tetrafluoroiodoethane, in an argon matrix at 14 K has been shown by FTTR spectroscopy to lead to the formation of a molecular complex. Irradiation of such complexes with near-infrared radiation]ed to the formation of rile corresponding iodoso-species (Z-IO). Radiation of wavelengths > 410 nm produced bands typical of iodyl-species (Z-IO2), while subsequent photolysis with UV-vis (a > 350 nm) radiation led to the development of bands attributed to hypoiodo-species (Z-OI) and to carbonyl complexes (carbonyl...XI, where X = H or F). Further photolysis using Pyrex- (lambda > 290 nm) and quartz-(lambda > 240 nm) filtered radiation increased the yield of the carbonyl complexes, which were the final products to be detected in the reaction series of each precursor with ozone. Sample annealing confirmed that the carbonyl complexes existed in two geometric arrangements, a molecular-pair type and a head-to-tail dipole-dipole type, In a similar study of each precursor deposited in a solid oxygen matrix the carbonyl complexes were the only species that could be identified, Thus by studying the reactions of ozone with these iodine-containing compounds It has been. possible to extend the number of known species having I-O-x bonds, to detect a number of carbony...XI complexes (X = M or F), and to clarify the mechanisms of the reactions.