Kinetics of the oxidation of selenium(IV) by neptunium(VII) in aqueous acidic perchlorate media
- Bucknell Univ., Lewisburg, PA
The Np(VII) oxidation of Se(IV) proceeds with two-to-one stoichiometry to yield Np(VI) and Se(VI) according to the empirical rate law -d(ln(Np(VII)))/dt = k/sub 1/(Se(IV)) + k/sub 2/(Se(IV))/sup 2/ with no detectable acid dependence. The apparent activation parameters are ..delta..H/sub 1/* = 7.43 +- 0.14 and ..delta..H/sub 2/* = 3.70 +- 0.65 kcal/mol and ..delta..S/sub 1/* = 19.7 +- 0.5 and ..delta..S/sub 2/* = -28.9 +- 2.2 eu. This rate law is accounted for by a mechanism involving the known dimerization of Se(IV) in acidic media and parallel paths for the oxidation of both monomeric and dimeric forms. At 25/sup 0/ and ..mu.. = 1.00 M, the specific rate constants for oxidation of the monomer (k/sub M/) and dimer (k/sub D/) are (1.07 +- 0.02) x 10/sup 3/ and (4.37 +- 0.17) x 10/sup 3/ M/sup -1/s/sup -1/, respectvely. The observed rate law and rate parameters are discussed in terms of, and are found to be consistent with, the established reactivity pattern exhibited by Np(VII) when oxidizing aquometal ions.
- OSTI ID:
- 7230599
- Journal Information:
- Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 15:11; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPOUNDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
HALOGEN COMPOUNDS
KINETICS
NEPTUNIUM COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PERCHLORATES
REACTION KINETICS
REDUCTION
SELENIUM COMPOUNDS
TRANSURANIUM COMPOUNDS