## Infinite-Dilution Diffusion Coefficients of Complex Ions from Solution Conductivity Data

journal contribution

posted on 18.02.1999 by David A. Dudek, Peter S. Fedkiw#### journal contribution

Any type of content formally published in an academic journal, usually following a peer-review process.

A technique is presented for determining infinite-dilution
diffusion coefficients of complex ions from solution conductivity data. The method involves measuring the conductivities of dilute solutions in which the distribution of
complex ions is systematically varied and statistically
regressing the data to an equation that effectively relates
individual ion diffusion coefficients to solution conductivity. The procedure is simple and requires no specialized
equipment to perform. Unlike methods that require a
concentration gradient, the solution composition is homogeneous and at equilibrium during measurements,
which is a significant advantage when labile complexes
are being studied. In this paper, diffusion coefficients of
cuprous cyanide complexes are determined. Statistical
analysis yields the infinite-dilution diffusion coefficients
of Cu(CN)

_{2}^{-}, Cu(CN)_{3}^{2-}, and Cu(CN)_{4}^{3-}at 25 °C as 1.43 × 10^{-5}± 9%, 1.08 × 10^{-5}± 9%, and 6.21 × 10^{-6}± 22% cm^{2}/s, respectively.