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Journal articles
Astatine Standard Redox Potentials and Speciation in Acidic Medium
Abstract : A combined experimental and theoretical approach is used to define astatine (At) speciation in acidic aqueous solution and answer the two main questions raised from literature data: does At(0) exist in aqueous solution and what is the chemical form of At(III), if it exists. The experimental approach considers that a given species is characterized by its distribution coefficient (D) experimentally determined in a biphasic system. The change in speciation arising from a change in experimental conditions is observed by a change in D value. The theoretical approach involves quasi-relativistic quantum chemistry calculations. The results show that At at the oxidation state 0 cannot exist in aqueous solution. The three oxidation states present in the range of water stability are At(-I), At(I) and At(III) and exist as At-, At+ and AtO+, respectively, in the 1 to 2 pH range. The standard redox potentials of the At+/At- and AtO+/At+ couples have been determined, the respective values being 0.36 ± 0.01 and 0.74 ± 0.01 V vs. NHE.
http://hal.in2p3.fr/in2p3-00450771
Contributor : Gilles Montavon <>
Submitted on : Wednesday, January 27, 2010 - 10:25:46 AM
Last modification on : Tuesday, July 21, 2020 - 10:34:03 AM
Long-term archiving on: : Friday, June 18, 2010 - 1:29:33 AM
Contributor : Gilles Montavon <>
Submitted on : Wednesday, January 27, 2010 - 10:25:46 AM
Last modification on : Tuesday, July 21, 2020 - 10:34:03 AM
Long-term archiving on: : Friday, June 18, 2010 - 1:29:33 AM
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JPCA_2010.pdf
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