An infrared spectroscopic study of the formation of adducts of Me(2)Cd in cryogenic thin films at -196 degrees C is reported. The formation of adducts has been monitored by measuring shifts in the position of bands arising from rho(CH3) and nu(as)(C-Cd-C) vibrations of the Me(2)Cd moiety and by activation of nu(sym)(C-Cd-C), a vibration which is infrared inactive in free Me(2)Cd. In the first series of experiments a number of potential chelating donor ligands were studied. Thus it is shown that Me(2)NCH(2)CH(2)NMe(2) (TMEDA) coordinates strongly to Me(2)Cd under these conditions. The adduct formed in the cryogenic film almost certainly has the same structure as in the gas phase, i.e., where the TMEDA ligand is chelating. Similar strong interactions with Me(2)Cd in cryogenic films are observed with the ligand Me(2)NCH(2)CH(2)N(Me)CH(2)CH(2)NMe(2) (PMDETA) and for the oxygen species MeOCH(2)CH(2)OMe (DME) and MeOCH(2)CH(2)OCH(2)CH(2)OMe ("diglyme"). By contrast the P-donor Me(2)PCH(2)CH(2)PMe(2) (TMDPE) gives only a weak interaction as do the cyclic molecules 1,4-dioxane, 1,4-thioxane, and 1,4-dithiane. The sulfur donors diethyl sulfide (Et(2)S), ethylene sulfide (EES), thiirane), and propylene sulfide (PES, methyl thiirane) show some interaction to Me(2)Cd. By contrast there is no evidence for any interaction between carbonyl sulfide (OCS) and Me(2)Cd under the same conditions. It is likely that all adducts detected have a 1:1 stoichiometry. The strength of adduct formation to Me(2)Cd shown by these donor molecules is discussed in terms of the proton affinity of the Lewis base.