Gas phase observation and microwave spectroscopic characterization of formic sulfuric anhydride

Abstract

An unexpected gaseous sulfur species Sulfuric acid plays a central role in both industrial and atmospheric contexts. As such, the behavior of SO 3 mixtures in gas phases has been studied for over a century. In gas-phase experiments on wet SO 3 and formic acid, Mackenzie et al. discovered a previously unrecognized covalent adduct: formic sulfuric anhydride, or HC(O)OSO 3 H. The combination of microwave spectroscopy and theoretical calculations reveals its structural properties. The compound may play a role in the nucleation of atmospheric aerosols by serving as an intermediate to H 2 SO 4 formation. Science , this issue p. 58