Growth habits of polar organic crystals are mainly determined by : (1) the internal structures of the crystals; and (2) the interactions of solvent molecules with the growth interfaces, particularly with two polar faces. Since polar organic crystals have noncentric structures, the existence of polar axis (axes) in the crystals has a significant effect on the molecular arrangement and on the crystal growth. On the other hand, different interface structure of two polar faces have different interaction with solvent molecules, solvent absorption on these faces are different. Therefore, the relative growth rates of these faces are different and thus lead to the habit modification. Based on these points, the molecular packing, interface structure and interface-solvent interactions of several polar organic crystals with a structure A-C6H4-D such as 4-amino-4'-nitrodiphenyl sulfide (ANDS), o-dicyanovinyl anisole (DIVA), N-4-nitrophenyl-(L)-prolinol (NPP) and 4-nitro-4'-methyl-benzilidine aniline (NMBA) have been investigated from the standpoint of crystal chemistry and structural perspectives. It is possible that growth habits of polar organic crystals can be controlled based on the interface-solvent interactions by choosing a suitable solvent or tailor-made additive.

Key words: CRYSTAL GROWTH, SOLVENT EFFECT, POLARITY, BENZALANILINE