Crystal Growth and Molecular Crystal Growth Modification

Abstract

Crystals have been described as the supermolecule par excellence , and hence it is important to have an understanding of how crystals grow and how to control the growth processes. The fundamentals of crystal growth are discussed, including recent developments such as two‐step nucleation theory and the concept of mesocrystals. The mesocrystals are formed by the aligned assembly of nanoparticles, and lead to products that are difficult, in some cases, to differentiate from genuine single crystals. The many different mechanisms by which impurities and additives can influence crystal growth are given, with an emphasis on the complexity associated with studying these systems. The control of crystal growth using tailor‐made additives is described, with particular application to molecular crystal systems. Examples focus on glycine, and include morphology control, determination of absolute configuration of a molecule, determination of crystal polarity, and polymorph control.

Electrochemical Crystallization of Organic Molecular Conductors: Electrode Surface Conditions for Crystal Growth

“…If the concentration is between the solubility and the supersolubility that induces spontaneous nucleation, a nucleus is formed by some stimuli, which leads to crystal growth. 9 It is well-known that common stimuli that destabilize the metastable supersaturated state include very fine dust in the solution or a scratch or flaw on the wall of the vessel. In electrochemical crystal growth, the supersaturation state is achieved only around the electrode, so it is highly likely that nucleation is promoted at scratches or flaws on the electrode surface.…”