Nucleation of one polymorph by another.

Nucleation of one polymorph by another has been observed directly in the melt crystallization of d-mannitol and d-sorbitol. The new polymorph nucleated on an existing one and grew to dominate the end product. This effect is relevant to controlling polymorphism in the manufacture of specialty chemicals and to developing theories of polymorphic nucleation and concomitant polymorphs, for which current efforts emphasize homogeneous nucleation of alternative polymorphs.