Effect of the addition of oxo-anions MoO42-, SiO42-, HPO42- and HCO3-on the corrosion and passivation of tin in a synthetic medium similar to industrial water has been studied by using electrochemical techniques. The results show that tin manifests a passivation phenomenon with breakdown of passivity. Addition of oxo-anions leads to retard a breakdown of passivation and the inhibition of pitting process of tin. The more marked inhibiting effect is obtained in the presence of MoO42- and SiO42-. The detailed study of the influence of the MoO42-shows that the pitting sensitivity of tin decreases when the molybdate concentration increases in solution. Then, these ions offer a good efficiency even at high temperature and for a chloride concentration up to 0.5 M. (c) 2006 Elsevier B.V. All rights reserved.