The adsorption and reaction of[HRe(CO)(5)] on ultrathin MgO(111) and on amorphous SiO2 films grown on a Mo(110) substrate were investigated with infrared reflection-absorption spectroscopy and temperature-programmed desorption. Similar adsorption and reaction chemistry were observed for samples prepared on both MgO(111) and SiO2 surfaces. [HRe(CO)(5)] was physisorbed in multilayers at 100 K. A fraction of the [HRe(CO)(5)] present in multilayers desorbed at 200 K, and as the temperature was raised, more strongly bound species were formed, which desorbed at 340 K. Heating of the sample in the range 100-300 K produced rhenium pentacarbonyls such as [Re(CO)(5){OM}] (M = Mg, Si), as indicated by the infrared spectra. Species suggested to be [Re(CO)(4){OM}](2) (M = Mg, Si) were formed in the temperature range 100-350 K, as indicated by the infrared spectra and a comparison of the spectra with those observed for samples prepared similarly from [Re-2(CO)(10)]. Heating to 400-500 K resulted in significant decarbonylation. The major species formed on both surfaces during this decarbonylation were surface-bound rhenium tricarbonyls, identified by infrared spectroscopy as [Re(CO)(3){OM}(3)] (M = Mg, Si). These results demonstrate strong parallels between the chemistry of rhenium carbonyls adsorbed on metal oxide thin films and those adsorbed on metal oxide powders.