Laboratory Measurements of Ferric Chloride (FeCl3) under Venusian Conditions

IF 2.9 3区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

ACS Earth and Space Chemistry Pub Date : 2025-07-23 DOI:10.1021/acsearthspacechem.5c00132

Joanna V. Egan*, Alexander D. James and John M. C. Plane*,

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Abstract

Ferric chloride (FeCl₃) in sulfuric acid cloud droplets has been proposed to explain the inhomogeneous near-ultraviolet (UV) absorption visible at the Venusian cloud tops. However, the absorption spectrum of FeCl₃ in concentrated sulfuric acid does not appear to have been measured previously; here we report measurements under appropriate conditions of temperature and H₂SO₄/H₂O solution strengths. The choice of solvent has a significant effect on the measured spectrum. The reaction of FeCl₃ in aqueous H₂SO₄ to form ferric sulfate (Fe₂(SO₄)₃) was shown to be suppressed by adding HCl to the solution (as would occur in the Venusian atmosphere). The FeCl₃ spectrum in sulfuric acid is shown to be in good agreement with observations of the unknown absorber in Venus’ atmosphere. The presence of Fe₂(SO₄)₃, which absorbs strongly below 320 nm, should be considered when reconstructing Venusian spectra to avoid misattribution of absorption in this spectral region to SO₂, potentially leading to an overestimation of the SO₂ cloud top concentrations.

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金星条件下氯化铁（FeCl3）的实验室测量

硫酸云滴中的氯化铁（FeCl3）被用来解释金星云顶可见的不均匀近紫外（UV）吸收。然而，FeCl3在浓硫酸中的吸收光谱似乎没有被测量过；在这里，我们报告在适当的温度和H2SO4/H2O溶液强度条件下的测量。溶剂的选择对测得的光谱有显著的影响。FeCl3在H2SO4水溶液中生成硫酸铁（Fe2(SO4)3）的反应被证明可以通过在溶液中加入HCl来抑制（就像在金星大气中发生的那样）。硫酸中的FeCl3光谱与金星大气中未知吸收剂的观测结果一致。在重建金星光谱时应考虑Fe2(SO4)3在320 nm以下强烈吸收的存在，以避免将该光谱区域的吸收错误地归因于SO2，从而可能导致对SO2云顶浓度的高估。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

ACS Earth and Space Chemistry Earth and Planetary Sciences-Geochemistry and Petrology

CiteScore

5.30

自引率

11.80%

发文量

249

期刊介绍： The scope of ACS Earth and Space Chemistry includes the application of analytical, experimental and theoretical chemistry to investigate research questions relevant to the Earth and Space. The journal encompasses the highly interdisciplinary nature of research in this area, while emphasizing chemistry and chemical research tools as the unifying theme. The journal publishes broadly in the domains of high- and low-temperature geochemistry, atmospheric chemistry, marine chemistry, planetary chemistry, astrochemistry, and analytical geochemistry. ACS Earth and Space Chemistry publishes Articles, Letters, Reviews, and Features to provide flexible formats to readily communicate all aspects of research in these fields.