ABSTRACT
In the early twentieth century, Joel H. Hildebrand de©ned a measurement of solubility behavior, quanti©ed by what he termed cohesive energy density, that enabled solubility parameters to be derived by measurements of evaporation. ¤is resulted in a relative scale that could be used to predict the solubility behavior of solvents and mixtures through numeric calculation. Hansen re©ned this approach by separating the single Hildebrand parameter into three values for dispersion, polarity, and hydrogen bonding energies, which Teas then abstracted into fractional contributions, thus allowing these three coordinates to be plotted on a simple triangular graph (a development that sacri©ced some precision for the ability to clearly describe, calculate, and predict complex solubility behavior).
