The chemical environment of Cu(II) adsorbed to the boehmite (AlOOH) surface at pH 6.5 is examined by electron paramagnetic resonance and X-ray absorption spectroscopy, Adsorbed Cu(II) is always coordinated by four oxygens in an axially symmetric Ligand field when adsorbed under our experimental conditions, The Cu-O bond distance is approximately 1.94 Angstrom. An oriented, inner-sphere Cu(II) surface complex is observed at low surface loading (<0.,2 mu mol/M-2). A second population of Cu(OH)(N) (H2O)(X)((2-N)+) outer-sphere complexes is proposed at higher surface loadings to explain X-ray absorption fine structure results, Cu(II) strongly resists any tendency to form a surface precipitate on boehmite at pH 6.5, The presence of specifically adsorbing anions had little effect on the local chemical environment of adsorbed Cu(II),