Interaction of ZnS with oxygen at 823, 873, and 923 K was studied using Fourier transform infrared spectroscopy (FTIR). The reaction of ZnS with oxygen was found to be pressure dependent. At 823 K the reaction products during oxygen exposures of 5 x 10(-3)-4 x 10(-2) Torr were adsorbed sulfur dioxide and sulfite, while at oxygen pressures greater than 4 x 10(-2) Torr sulfate was the most prominent species. At 873 K, adsorbed SO2 and sulfite were the only species formed below 4 x 10(-2) Torr of oxygen but sulfate started to form at 4 x 10(-2) Torr. However, at 873 K adsorbed SO2 was the most prominent species observed for all oxygen pressures. The reaction profile at 923 K was similar to that at 873 K, but there were more types of adsorbed SO2. On the basis of the experimental results, a mechanism for the reaction of ZnS with oxygen is proposed.