We report the discovery of new polymorphic forms of solids by exploiting a solid-state NMR technique that has been developed for in situ monitoring of the evolution of crystallization processes. The capability of the technique to reveal the existence of new polymorphic forms of molecular solids is illustrated by the discovery of two new polymorphs of methyldiphenylphosphine oxide and a new solid form of the 1,10-dihydroxydecane/urea system.
Keywords: crystallization; in situ techniques; polymorphism; solid-state NMR.