Thus, molecules with lower Ra values and more similar HSPs are more likely to form a soluble mixture. Solubility predicVon is achieved by experimentally determining the maximum suitable Ra value (R0). This 'cut-off' defines the radius of the resulVng 'solubility sphere' centered on the solute. Here, all solvents within the sphere (and so Ra ≤ R0) are predicted to dissolve the solute.