Racemizable systems crystallizing as conglomerate and spontaneous symmetry breaking

Heterogeneous equilibria are reviewed in binary and ternary systems of enantiomers without and with in situ racemization. The twofold symmetry between the two chiral components is also found in the phase diagrams except for stable conglomerate forming systems associated with a fast in situ racemization in the liquid phase. In this particular case, a gentle attrition speeds up the irreversible evolution of the system towards a spontaneous symmetry breaking, i.e., a single crystallized enantiomer in equilibrium with its racemic solution. This final evolution is predicted to reach the limit of miscibility in the solid state for conglomerate forming system with partial solid solution and in situ racemization.