Structure of add rain complex determined

A key intermediate in the formation of atmospheric sulfuric acid has been observed spectroscopically in the gas phase for the first time by chemists at the University of Minnesota, Minneapolis. The observation may open a new window into the study of the chemistry of acid rain. Sulfuric acid (H 2 S0 4 ) is one of the primary constituents of acid rain. Scientists believe that it forms when sulfur dioxide (S0 2 ), produced from smokestacks and other sources, is oxidized in the atmosphere to sulfur trioxide (S0 3 ). In one long-held mechanism, S0 3 then interacts with water to form a weakly bound H 2 0·S0 3 complex. In this complex, proton transfer from the water moiety to S0 3 leads to formation of a molecule of sulfuric acid. However, direct observation of the H 2 0·S03 complex has been an elusive goal. The difficulty is that S0 3 and H 2 0 react violently under ordinary conditions. So an H 2 0·S0 3 intermediate, if formed, would immediately proceed to the final H 2 S0 4 ...