Chlorosulfenic Acid: An Important Linker in the Coupled Sulfur and Chlorine Chemistry in the Venusian Atmosphere

The coupled sulfur and chlorine chemistry plays an important role in the chemical cycle of the Venusian atmosphere. However, the reactivity of sulfur monoxide (SO) toward hydrochloric acid (HCl), two abundant reactive gases in the Venusian atmosphere remains hitherto unknown. In this work, we report the generation, spectroscopic characterization, and photochemistry of chlorosulfenic acid (HOSCl), a simple molecule that acts not only as a potential candidate for the near-UV absorber but also as an important linker in the coupled sulfur and chlorine chemistry in the Venusian atmosphere. This molecule has bright absorption from 330 to 440 nm. The photochemistry of HOSCl at 365 nm yields SO and HCl as a novel hydrogen-bonded molecular complex in a cryogenic Ar-matrix at 10 K, and the subsequent irradiation at 193 nm leads to recombination of the two fragments by reformation of HOSCl. The photochemistry of HOSCl underscores its importance in the photochemical models of the sulfur and chlorine species in Venusian atmosphere.