Acetonitryle - Water binary mixtures and their assumed internal structures

The H-1-NMR spectra of liquid binary mixtures, acetonitryle (ACN) - water (H2O), were recorded at 298 K and the spectral parameters, Delta delta(ACN-H2O) were evaluated. The surface tensions (sigma(12)) were measured at 298.15 K. From literature values of density (d(12)), viscosity (eta(12)), relative permittivities (epsilon(12)) and measured surface tensions the values of molar volumes (V-12) and their deviations from "ideality" were calculated. Further on the temperature coefficients of relative permittivity, alpha(12) = (1/epsilon(12)).[d epsilon(12)/d(1/T)], were evaluated. These structural parameters as functions of concentration suggest the formation of the intermolecular "complexes" of the ACN . 2H(2)O, ACN . H2O, 2 ACN . 3H(2)O and 2 ACN . 3 H2O types.