Molecular dynamics (MD) simulations of gamma-Al2O3, using a pairwise additive interaction potential of Pauling’s type with four different radii for aluminum atoms, were analysed in order to determine the influence of the radius on the modification of coordination numbers of Al relative to the ideal structure, at two different temperatures of 300 and 1500 K. It is found that the best choice is the radius of penta-coordinated aluminum, reproducing structural and vibrational properties of the compound in excellent agreement with experimentally observed properties.