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| Titel |
Thermodynamics of reactions of ClHg and BrHg radicals with atmospherically abundant free radicals |
| VerfasserIn |
T. S. Dibble, M. J. Zelie, H. Mao |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 21 ; Nr. 12, no. 21 (2012-11-06), S.10271-10279 |
| Datensatznummer |
250011565
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| Publikation (Nr.) |
 copernicus.org/acp-12-10271-2012.pdf |
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| Zusammenfassung |
| Quantum calculations are used to determine the stability of reactive gaseous
mercury (Hg(II)) compounds likely to be formed in the Br-initiated oxidation
of gaseous elemental mercury (Hg(0)). Due to the absence of any evidence,
current models neglect the possible reaction of BrHg with abundant radicals
such as NO, NO2, HO2, ClO, or BrO. The present work demonstrates that
BrHg forms stable compounds, BrHgY, with all of these radicals except NO.
Additional calculations on the analogous ClHgY compounds reveal that the
strength of the XHg-Y bond (for X = Cl, Br) varies little with the identity
of the halogen. Calculations further suggest that HO2 and NO3 do not
form strong bonds with Hg(0), and cannot initiate Hg(0) oxidation in the gas
phase. The theoretical approach is validated by comparison to published data
on HgX2 compounds, both from experiment and highly refined quantum
chemical calculations. Quantum calculations on the stability of the anions of
XHgY are carried out in order to aid future laboratory studies aimed at
molecular-level characterization of gaseous Hg(II) compounds. Spectroscopic
data on BrHg is analyzed to determine the equilibrium constant for its
formation, and BrHg is determined to be much less stable than previously
estimated. An expression is presented for the rate constant for BrHg
dissociation. |
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