Editing Crystallization (section)

{{Short description|Process by which a solid with a highly organized atomic or molecular structure forms}}
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{{Crystallization}}
'''Crystallization''' is a process that leads to solids with highly organized [[Atom|atoms]] or [[Molecule|molecules]], i.e. a [[crystal]]. The ordered nature of a crystalline solid can be contrasted with [[amorphous solids]] in which atoms or molecules lack regular organization. Crystallization can occur by various routes including [[Precipitation (chemistry)|precipitation]] from solution, [[freezing]] of a liquid, or [[Deposition (phase transition)|deposition]] from a gas. Attributes of the resulting crystal can depend largely on factors such as [[temperature]], air [[pressure]], cooling rate, or [[Solution (chemistry)|solute concentration]].

Crystallization occurs in two major steps. The first is [[nucleation]], the appearance of a crystalline phase from either a [[Supercooling|supercooled]] liquid or a [[supersaturation|supersaturated]] solvent. The second step is known as [[crystal growth]], which is the increase in the size of particles and leads to a crystal state. An important feature of this step is that loose particles form layers at the crystal's surface and lodge themselves into open inconsistencies such as pores, cracks, etc.

Crystallization is also a chemical solid–liquid separation technique, in which [[mass transfer]] of a solute from the liquid solution to a pure solid crystalline phase occurs. In [[chemical engineering]], crystallization occurs in a [[crystallizer]]. Crystallization is therefore related to [[Precipitation (chemistry)|precipitation]], although the result is not amorphous or disordered, but a crystal.