Document Detail


Antarctic stratospheric chemistry of chlorine nitrate, hydrogen chloride, and ice: release of active chlorine.
MedLine Citation:
PMID:  17744362     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
The reaction rate between atmospheric hydrogen chloride (HCl) and chlorine nitrate (ClONO(2)) is greatly enhanced in the presence of ice particles; HCl dissolves readily into ice, and the collisional reaction probability for ClONO(2) on the surface of ice with HCl in the mole fraction range from approximately 0.003 to 0.010 is in the range from approximately 0.05 to 0.1 for temperatures near 200 K. Chlorine (Cl(2)) is released into the gas phase on a time scale of at most a few milliseconds, whereas nitric acid (HNO(3)), the other product, remains in the condensed phase. This reaction could play an important role in explaining the observed depletion of ozone over Antarctica; it releases photolytically active chlorine from its most abundant reservoir species, and it promotes the formation of HNO(3) and thus removes nitrogen dioxide (NO(2)) from the gas phase. Hence it establishes the necessary conditions for the efficient catalytic destruction of ozone by halogenated free radicals. In the absence of HCl, ClONO(2) also reacts irreversibly with ice with a collision efficiency of approximately 0.02 at 200 K; the product hypochlorous acid (HOCI) is released to the gas phase on a time scale of minutes.
Authors:
M J Molina; T L Tso; L T Molina; F C Wang
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Science (New York, N.Y.)     Volume:  238     ISSN:  0036-8075     ISO Abbreviation:  Science     Publication Date:  1987 Nov 
Date Detail:
Created Date:  2010-06-08     Completed Date:  2010-07-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0404511     Medline TA:  Science     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1253-7     Citation Subset:  -    
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