Crystal growth mechanism determined by crystallographic and affine symmetries

Crystallographic and affine symmetries are the important factors influencin g crystal growth. In order to grow quickly, particularly in the initial sta ge, a crystal requires low indexed faces with thin growth layers. Such peri ods are produced when the net plane distances are divided by symmetries. pr edominantly those with glide components. The effectiveness of crystallograp hic and affine screw axes and glide planes, and hence the growth rate of th ese faces, depends on the position of the symmetry elements in relation to the lattice planes. The influence of local affine symmetries on crystal gro wth is not yet known. An analysis was carried out of the symmetries present in the crystal structures of 2,3-dichloro-1,4-naphthoquinone, amidopyrine (P (1) over bar) and glycolic acid (P2(1)/c), each with two crystallographi cally independent molecules in the asymmetric unit. The growth forms were c alculated.