Iron-sulfur chemistry can explain the ultraviolet absorber in the clouds of Venus.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38170780.
- Also identified by DOI 10.1126/sciadv.adg8826 and PMC identifier 10776003.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The clouds of Venus are believed to be composed of sulfuric acid (H<sub>2</sub>SO<sub>4</sub>) and minor constituents including iron-bearing compounds, and their respective concentrations vary with height in the thick Venusian atmosphere. This study experimentally investigates possible iron-bearing mineral phases that are stable under the unique conditions within Venusian clouds. Our results demonstrate that ferric iron can react with sulfuric acid to form two mineral phases: rhomboclase [(H<sub>5</sub>O<sub>2</sub>)Fe(SO<sub>4</sub>)<sub>2</sub>·3H<sub>2</sub>O] and acid ferric sulfate [(H<sub>3</sub>O)Fe(SO<sub>4</sub>)<sub>2</sub>]. A combination of these two mineral phases and dissolved Fe<sup>3+</sup> in varying concentrations of sulfuric acid are shown to be good candidates for explaining the 200- to 300-nm and 300- to 500-nm features of the reported unknown UV absorber. We, therefore, hypothesize a rich and largely unexplored heterogeneous chemistry in the cloud droplets of Venus that has a large effect on the optical properties of the clouds and the behavior of trace gas species throughout Venus's atmosphere.