In:
Angewandte Chemie, Wiley, Vol. 132, No. 19 ( 2020-05-04), p. 7675-7680
Abstract:
Mercury is a contaminant of global concern that is transported throughout the atmosphere as elemental mercury Hg 0 and its oxidized forms Hg I and Hg II . The efficient gas‐phase photolysis of Hg II and Hg I has recently been reported. However, whether the photolysis of Hg II leads to other stable Hg II species, to Hg I , or to Hg 0 and its competition with thermal reactivity remain unknown. Herein, we show that all oxidized forms of mercury rapidly revert directly and indirectly to Hg 0 by photolysis. Results are based on non‐adiabatic dynamics simulations, in which the photoproduct ratios were determined with maximum errors of 3%. We construct for the first time a complete quantitative mechanism of the photochemical and thermal conversion between atmospheric Hg II , Hg I , and Hg 0 compounds. These results reveal new fundamental chemistry that has broad implications for the global atmospheric Hg cycle. Thus, photoreduction clearly competes with thermal oxidation, with Hg 0 being the main photoproduct of Hg II photolysis in the atmosphere, which significantly increases the lifetime of this metal in the environment.
Type of Medium:
Online Resource
ISSN:
0044-8249
,
1521-3757
DOI:
10.1002/ange.v132.19
DOI:
10.1002/ange.201915656
Language:
English
Publisher:
Wiley
Publication Date:
2020
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514305-6
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505872-7
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1479266-7
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506259-7
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