Zw. Yu et al., A principle to correlate extreme values of excess thermodynamic functions with partial molar quantities, SCI CHINA B, 44(3), 2001, pp. 315-319
Excess thermodynamic properties are widely used quantitatively for fluids.
It was found that at constant temperature and pressure a molar excess quant
ity of a mutually miscible binary mixture at the extreme points equals the
excess partial molar quantities of the two components, i.e. F-1(E) = F-2(E)
= F-m(E), forming a triple cross point. The relationship is hold for prope
rties such as enthalpy, entropy, Gibbs free energy, and volume, and is appl
icable for excess functions with multi extreme points. Solutions at extreme
points can be referred to as special mixtures, Particularly for a special
mixture of Gibbs free energy, activity coefficients of the two components a
re identical.