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Abstract:Recommendations are made for standard potentials involving select inorganic radicals in aqueous solution at 25 °C. These recommendations are based on a critical and thorough literature review and also by performing derivations from various literature reports. The recommended data are summarized in tables of standard potentials, Gibbs energies of formation, radical pK a 's, and hemicolligation equilibrium constants. In all cases, current best estimates of the uncertainties are provided. An extensive set of Data Sheets is appended that provide original literature references, summarize the experimental results, and describe the decisions and procedures leading to each of the recommendations.

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Reports on the kinetics of the autoxidation of aqueous nitric oxide are discussed. It is concluded that the correct rate law is -d[NO]ldt = 4k,, [N012[0,] with k,, = 2 x lo6 M-' s-' at 25°C and that a recent report of a rate law zero order in NO is incorrect. . An important factor is the fugitive character of NO in oxygenated media, especially given the potential genotoxicity of species generated in NO autoxidation [6,7]. How, for example, can NO participate as a bioregulatory agent in oxygenated media despite its propensity to undergo autoxidation? A proper assessment of nitric oxide autoxidation under biological conditions depends on knowing the reaction kinetics, i.e. rate law and the relevant rate constants in aqueous media. The purpose of this correspondence is to point out that the rate law is now known with some confidence, despite potential confusion resulting from two recent reports that are incorrect. The correct rate law is -The gas phase autoxidation of NO is [8] 2N0 + O2 + 2N0,and the corresponding rate law has been shown to beThe stoichiometry cannot be the same in aqueous solution since NO, is unstable in this medium. A key question is whether the form of the rate law also differs in aqueous solution.The first detailed report on the aqueous autoxidation

Abstract:Inorganic radicals, such as superoxide and hydroxyl, play an important role in biology. Their tendency to oxidize or to reduce other compounds has been studied by pulse radiolysis; electrode potentials can be derived when equilibrium is established with a well-known reference compound. An IUPAC Task Group has evaluated the literature and produced the recommended standard electrode potentials for such couples as (O 2 /O 2 · -), (HO·, H +