Oxygen atoms adsorption and oxidation of the Si-rich 3C-SiC(001) 3 x 2 surface was investigated using Monte Carlo simulations. The adatom interactions were described using a lattice-gas model with interaction energies determined by density functional theory calculations. Simulations were performed for oxygen coverages ranging from 5 to 30%. Oxygen adatom structures tend to form clusters on the surface which are similar to those seen in scanning tunneling microscopy. (C) 2008 Elsevier B.V. All rights reserved.