A combination of aqueous thermodynamics, anodic polarization tests, and scanning electron microscopy was used to study the pitting behavior of Cd monocrystals in a phosphate-buffered (pH 11.2) solution of 0.1 M NaCl. Pitting occurred in the passive region where the most stable passive film was Cd(OH)(2). The film thickness was estimated to be similar to 4 x 10(-9) m. Pitting potentials were not reproducible, being variable within surfaces of the same orientation and between different orientations. Variability was attributed to the effects of structural defects in the passive film and the potential scan rate influencing pit site nucleation and pit growth behavior. Sustained pitting was not possible below - 0.472 V-SHE. Early stages of pitting produced crystallographic facets consistent with (0001), (10 (1) over bar0), and {11 (2) over bar0} planes, with the morphology becoming increasingly complex with pit growth. pH decreased to below 8.5 in the growing pit and increased the influence of chloride species on localized dissolution behavior. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3207569] All rights reserved.