Browsing by Author "Hill, R. John"

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    Kinetics and Mechanism of the Reduction of Manganese(III) in Perchloric Acid at a Platinum Electrode
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Rosseinsky, David R.; Hill, R. John
    The electrode kinetics at 25°C of the reduction of manganese(III) on an oxidised platinum surface confirms an unusually low transfer coefficient of 0.26. Interpretation involving a comparison with a correlation of hydrolytic constants of similar trivalent cations and their several redox potentials points to a hydroxo- or oxo-bridged transition state. The MnHi/Mn11 conditional standard electrode potential was observed to be 1.535 V at ionic strength 3.31 mol dm-3 against H2|HC1O4(3 mol dm-3), NaClO4 (0.31 mol dm-3).
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    Manganese(in) and its Hydroxo- and Chloro-complexes in Aqueous Perchloric Acid: Comparison with similar Transition-metal(m) Complexes
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (12), 1974) Rosseinsky, David R.; Nicol, Michael J.; Kite, Kenneth; Hill, R. John
    At 25°C the formation constant of MnCl2+ is found by spectrophotometry to be 13.2 ± 0.9 dm3 mol–1 at ionic strength 3.26 mol dm–3; for MnCl+2 the value is 1.1 ± 0.7 dm3 mol–1. Increase in the number of chloride ions in complexes results in longer wavelengths for the corresponding absorption maxima. In the absence of chloride the hydrolysis constant of MnIII at ionic strength 5.6 mol dm–3 is found from voltammetry and potentiometry to be 1.05± 0.26 mol dm–3. Aged managanese(III) is found to be 15–25% polymeric, from both kinetic and e.m.f. measurements. Comparison of formation constants for halogeno- and hydroxo-complexes of M3+(first transition series) shows that a combination of charge-transfer, ligand-field and coulomb interactions underlies the observed sequences; the dipole moment of OH– is also a factor.