CRYSTAL-CHEMISTRY AND SOLVENT EFFECTS IN POLYMORPHIC SYSTEMS - SULFATHIAZOLE

Sulfathiazole, a compound that forms four known crystal structures, ha s been examined with a view to understanding its polymorphism. A graph set approach was used to classify the structural differences and simi larities of the polymorphs, the results of which indicated packing mot ifs common to three of the four structures. By combining this analysis with experimental morphological data, it has been possible to examine the origins of the observed solvent dependence of polymorph appearanc e in this system. In particular, the possible link between the observe d hydrogen-bond motifs of each form and the associated processes of nu cleation and crystal growth from n-propanol, nitromethane, ethanol, wa ter and ammonia solution, have been considered.