Abstract
The Wilson equation is modified so that it contains only one adjustable constant per binary system. In describing binary behavior the new equation is inferior to the original Wilson but superior to the Van Laar equation. In developing ternary behavior from binary data, the new equation seems to be comparable to the original Wilson but definitely superior to the Van Laar equation.Binary and ternary vapor‐liquid equilibrium behavior has been successfully predicted from one γ° value per binary only.