A method is presented for the calculation of the habit of organic crystals from known crystal structure and symmetry. Calculated morphologies are found to be in good agreement with observations for crystals grown by sublimation. To obtain the habit of solution-grown crystals solvent/solute interactions at the crystal/solution interface must be considered. It was assumed that the solvent affects the habit of crystals through preferential adsorption of solvent molecules on specific crystal faces; the need to remove the solvation layer prior to the deposition of oncoming crystal layers causes retardation of growth of these faces relative to their growth rate from the vapor. Changing the relative growth rates of the various faces leads to a change in crystal shape. Electrostatic potential maps at closest approach distances were used for the study of the relative polarities of the various crystal faces, information which is crucial for the prediction of the habits of crystals obtained from solution in polar or nonpolar solvents.

When crystals of organic compounds are grown in the presence of growth inhibitors, there is a change in crystal morphology. A stereochemical correlation exists between the crystal structure, its modified morphology, and the molecular structure of the inhibitor. This correlation has been successfully exploited for the efficient resolution of conglomerates, the engineering of organic crystals with desired morphologies, the direct and relative assignment of the absolute configurations of chiral molecules and crystals, and for the design of a new model for the spontaneous generation of optical activity. In an analogous way dissolution of organic crystals in the presence of these growth inhibitors induces etch pits at preselected faces. The effect of solvent on crystal growth has been analyzed in some model systems. The experimental results are complemented by atom-atom potential energy calculations.

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