Velocity correlations in aqueous electrolyte solutions from diffusion, conductance and transference data. Application to concentrated solutions of cadmium iodide

Abstract

Tracer-diffusion coefficients for the Cd and I constituents and of water in aqueous CdI₂ solutions have been measured up to concentrations of ca. 2 mol dm^–3 at 298.16 K. In conjunction with other transport thermodynamic data, these measured values have been used to calculate velocity cross-correlation coefficients for the CdI₂/H₂O system. Trends in these coefficients due to complex formation are examined and discussed. Anomalously high mobilities for negative complexes of cadmium are needed to explain the observation of negative transference numbers.