Calorimetric enthalpy of reaction of cobalt(III) with iron(II) in aqueous perchloric acid, and the standard electrode potential for cobalt(III)-(II)

Abstract

Literature measurements of ΔH for Co^III+ Fe^II differ markedly, leading to very different estimates of E° for Co^III+ e = Co^II. The present measurement gives, respectively, –94.3 kJ mol^–1, and 1.73 V (25°C, ∼2.3 mol dm^–3 HClO₄) estimated with an assumed spin-only entropy change.