The performance of five existing models for predicting the electronic properties of passive oxide films on carbon steel that are exposed to synthetic alkaline media representing concrete pore solutions was investigated. It was found that the two donor band model, which is based on the presence of two discrete donor bands each with a Gaussian distribution of energy states for an n-type semiconductor, most accurately predicts experimental measurements. The model supports the experimental data that show an increase in the deep donor density and width of the deep donor band with increasing passivation time. A comparison of films formed in different passivating solutions revealed the potential of this model to predict the passive film electronic properties in environments not yet studied experimentally. (C) 2015 The Electrochemical Society. All rights reserved.