Effects of Additives, Solvents, and Impurities

Chapter 3 of this text describes in detail the mechanisms and effects of various components of a solution on the resulting crystal size, morphology (habit), growth rate, and purity. Here we simply 

There has been a series of systematic studies of the effect of impurities and tailor-made additives on the shape of crystals grown from solution (Addadi et al. 1982 Berkovitch-Yellin 1985 Weissbuch et al. 1999.) They used amino acids and amino acid derivatives as model solutes. By combining habit observations with crystal structure and molecular orientation, they were able to rationalize a number of effects, including resolution of steroisomers. Hopefully, further studies in this area will provide a rational basis for the many impurity and additive effects found during crystallization of biochemicals. 

Solvent Effects. Changes of solvent, as in the use of alcohols as anti-solvents for precipitation from aqueous solution, may also influence particle shape through altering growth kinetics on 

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