Polymorphism and solid phase transition in solution

Many substances can appear in different solid phases if the conditions of the growth medium allow. These solid phases may be polymorphs, solvates, isomers, microcrystalline solids or amorphous.

This article focuses on polymorphs and "pseudopolymorphs".

After definitions and a presentation of the issues involved in the use of polymorphs, we will briefly review the nucleation and growth of crystalline phases in solution, which are necessary to understand the mechanisms encountered to obtain one polymorphic solid phase rather than another, or which control the final facies of the crystals produced. The third part will also be devoted to solid phase transitions, in particular polymorphism. Now that the thermodynamic and kinetic foundations have been laid, the fourth part is devoted to the basic data to be acquired experimentally in the laboratory for the development of the desired solid phase. Finally, strategies for obtaining and controlling a polymorph will be presented and discussed in the fifth part.