The interaction of Cr(CO)6, MO(CO)6, and W(CO)6, with dehydroxylated active zirconia (prepared by thermolysis of a zirconium sulfate) has been studied by in situ IR spectroscopy. Adsorption of the three metal carbonyls takes place via O-bonding between a CO ligand and Lewis acid sites on the zirconia surface. Two kinds of these sites (with different Lewis acid strength) have been identified using CO as a spectroscopic probe. Formation of surface adducts between the zirconia support and the metal carbonyls was found to labilize CO ligands. Reversible decarbonylation of the adsorbed metal carbonyls was observed when pumping at room temperature. Subsequent admission of CO into the IR cell regenerates the hexacarbonyl surface adducts. The stability of these adducts (toward decarbonylation) was found to follow the order W(CO)6 > Cr(CO)6 > MO(CO)6.