THE STRUCTURE OF COARSE CRYSTAL-SURFACES - THE (00(1)OVER-BAR) FACE OF K2CR2O7 CRYSTALS GROWN FROM AQUEOUS-SOLUTION AS AN EXAMPLE

The surface structure of the coarse (0 0 (1) over bar) face of potassi um bichromate (K2Cr2O7) was studied in-situ and ex-situ with the help of optical microscopy, atomic force microscopy and scanning electron m icroscopy. A multitude of features, like unit cell height steps, bunch es, macrosteps of which some are actually small facets, inclusions and spirals were observed. The observations lead to new ideas about the g rowth mechanisms of this face, in which the combined action of impurit y adsorption and volume diffusion plays a key role. These mechanisms m ay be responsible for the coarse growth on other crystals as well. (C) 1998 Elsevier Science B.V. All rights reserved.