On the possible roles of gaseous sulfur and sulfanes in the atmosphere of Venus

We discuss the possible importance of gaseous elemental sulfur (particularly S2S3 (thiozone) and S4) and sulfanes (H2Sn) in the lower atmosphere of Venus. These species absorb visible and near ultraviolet light. They can provide a local heating source which could drive convection in the 10‐40 km altitude region and may also contribute to the ultraviolet markings on the planet. Photodissociation of these species will result in non‐equilibrium concentrations of S and SH. This drives the lower atmosphere away from the thermochemical equilibrium species: COSH2Sand Sn and toward SO2 and possibly H2Sn. Some H2O is also converted to O2. We also discuss exothermic reactions which can provide local heating and light on the night‐side.