Surface films are obtained on Hg0.79Cd0.21Te and CdTe by treatment in a solution of 0.1 M Fe(CN)(6)(3-) (ferricyanide) in 0.5 M KOH. Composition profiles are obtained by X-ray photoelectron spectroscopy (XPS), and they reveal the presence of cadmium oxide (CdO) and elemental tellurium (Te-0). The film on Hg0.79Cd0.21Te is porous and thick (e.g. 800 Angstrom). whereas the film on CdTe is nonporous and thin (< 100 Angstrom). The presence of CdO instead of Cd(OH)(2) and the presence of Te-0 despite the highly oxidizing Fe(CN)(6)(3-) ions are not predicted by equilibrium thermodynamics; they are due to the film growth kinetics. The origin of the surface chemical films is discussed in detail.