Extension rules

The statement that the solubility is higher for metastable phases than for stable phases can be proved by a relatively simple imaginary experiment. Hence, it follows that the metastable extensions of the solubility limit curves, surfaces, and hypersurfaces in the phase diagrams of binary, ternary, and multicomponent systems cannot run in the single-phase solvent region. A special case for binary systems is the Hollmann’s rule.