Polymorphism and solvatomorphism 2009.

Research papers and issued patents involving polymorphism (i.e., crystal systems for which a substance can exist in structures characterized by different unit cells, but in which each of the forms has exactly the same elemental composition) and solvatomorphism (i.e., systems in which the crystal structures of the substance are defined by different unit cells, but wherein these unit cells differ in their elemental composition through the inclusion of one or more molecules of solvent) have been summarized in an annual review. The works cited in this review were published during 2009, and were sourced from the major physical, crystallographic, and pharmaceutical journals. The review is divided into sections that cover articles of general interest, computational and theoretical studies, preparative and isolation methods, structural characterization, properties of polymorphic and solvatomorphic systems, studies of phase transformations, effects associated with secondary processing, and US patents issued during 2009.