A New Expression for Excess Volumes of Binary Mixtures

A new expression for excess volumes of binary mixtures is derived. This equation contains four adjustable but physically-meaningful parameters: two non-randomness factors and two partial molar volumes at infinite dilution. The applicability of this equation is tested against data in the literature for several non-ideal mixtures, and it is found that this equation successfully expresses the experimental curves of excess volume, VE, over the entire concentration range. Furthermore, it is demonstrated that the non-randomness factors used in the excess volume expression can be used to estimate the excess Gibbs energy, GE, of binary mixtures based on the Wilson equation.