Surface-bound [CpW(CO)(3)](-) complexes were prepared by deprotonation of [HCpW(CO)(3)] on MgO, gamma-Al2O3, and K/Al2O3 and characterized by infrared and extended X-ray absorption fine structure (EXAFS) spectroscopies. On. the metal oxide surfaces, [CpW(CO)(3)](-) interacts with coordinatively unsaturated cations via C- and O-bonded carbonyl ligands. A carbonyl O atom can be envisaged as completing the coordination sphere of a {M(n+)} ion terminating the bulk metal oxide. Ion adducts containing one Sigma-CO- ligand per complex are formed on each metal oxide; this parallels the solution ion-pair chemistry of [CpW(C0)(3)](-) with K+, Mg2+, and Al3+. On highly dehydroxylated MgO and gamma-Al2O3, novel bis(isocarbonyl) adducts are formed in which the [CpW(CO)(3)] moiety is inferred to bridge {M(n+)} ions via Sigma-CO- ligands. The crystallographically characterized compound [(AlMe(2))CpW(CO)(3)](2) is cited as precedent for this bonding geometry in solution organometallic chemistry.