Chiral symmetry breaking in crystallization: the role of convection

Chiral symmetry breaking in stirred crystallization of sodium chlorate ( NaClO3) occurs via the production of secondary crystals from a single "mother crystal." Martin, Tharrington, and Wu [Phys. Rev. Lett. 77, 2826 (1996)] investigated this phenomenon and concluded that it was mechanical crushing of a crystal by the stir bar, not convection, that produces secondary crystals from a single crystal. Here we report the generation of secondary crystals of sodium chlorate when a saturated solution of sodium chlorate is simply made to flow over a sodium bromate ( NaBrO3) crystal. This clearly shows that fluid flows alone can generate and disperse secondary nuclei.