Diffusion Coefficients of Cuprous and Cupric Ions in Electrolytes with High Concentrations of Bromide Ions

Abstract

This study examines the diffusion coefficients of cuprous and cupric ions in aqueous solutions containing 4–6 mol·dm–3 bromide ion. Under these conditions, the majority of the Cu2+ species is the complex CuBr4–2, and the majority of Cu+ species is the complex CuBr3–2. Diffusion coefficients were obtained for temperatures ranging from 298 to 334 K via a rotating disk electrode and the Levich relationship. Diffusion coefficients for the cuprous bromide complex were found to be between 11.9 and 19.1 × 10–6 cm2·s–1. Diffusion coefficients for the cupric bromide complex ranged between 4.5 and 12.0 × 10–6 cm2·s–1. Confidence intervals were calculated with reasonable uncertainties. The diffusion coefficients were found to be in good agreement with literature values of cuprous and cupric chloride complexes.