Kinetics and mechanism of oxidation of antimony(III) by keggin-type 12-tungstocobaltate(III) in aqueous hydrochloric acid medium

✍ Scribed by B. D. Bhosale; G. S. Gokavi

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 84 KB
• Volume: 35
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.10097

✦ Synopsis

Abstract

The reaction between Sb(III) and [Co^III^W~12~O~40~]^5−^ proceeds with two, one‐electron steps; formation of unstable Sb(IV) is the slow first step followed by its reaction with another oxidant in a fast step. The reaction rate is unaffected by the [H^+^] as there are no protonation equlibria involved with both the reactants, whereas the accelerating effect of chloride ion is due to the formation of an active chlorocomplex of the reductant, SbCl~6~^3−^. Increase in the ionic strength and decrease in the relative permittivity of the medium increases the rate of the reaction, which is attributed to the formation of an outer‐sphere complex between the reactants. The activation parameters were also determined and these values support the proposed mechanism. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 9–14, 2003