Editing Crystallization (section)

== Methods ==
Crystals can be formed by various methods, such as: cooling, evaporation, addition of a second solvent to reduce the solubility of the solute (technique known as [[antisolvent]] or drown-out), solvent layering, sublimation, changing the cation or anion, as well as other methods.

The formation of a supersaturated solution does not guarantee crystal formation, and often a seed crystal or scratching the glass is required to form nucleation sites.

A typical laboratory technique for crystal formation is to dissolve the solid in a solution in which it is partially soluble, usually at high temperatures to obtain supersaturation. The hot mixture is then filtered to remove any insoluble impurities. The filtrate is allowed to slowly cool. Crystals that form are then filtered and washed with a solvent in which they are not soluble, but is miscible with the [[mother liquor]]. The process is then repeated to increase the purity in a technique known as recrystallization.

For biological molecules in which the solvent channels continue to be present to retain the three dimensional structure intact, microbatch<ref>{{cite journal | last1=Chayen|first1=Blow|title=Microbatch crystallization under oil – a new technique allowing many small-volume crystallization trials|journal=Journal of Crystal Growth|date=1992|volume=122|issue=1–4|pages=176–180|doi=10.1016/0022-0248(92)90241-A|bibcode=1992JCrGr.122..176C}}</ref> crystallization under oil and vapor diffusion<ref>{{cite journal |last1=Benvenuti |first1=Mangani|title=Crystallization of soluble proteins in vapor diffusion for x-ray crystallography|journal=Nature Protocols|date=2007|volume=2|issue=7|pages=1633–1651|doi=10.1038/nprot.2007.198|pmid=17641629|doi-access=free}}</ref> have been the common methods.

=== Typical equipment ===
{{Expand section|date=March 2023}}
Equipment for the [[#Main crystallization processes|main industrial processes for crystallization]].

# ''Tank crystallizers''. Tank crystallization is an old method still used in some specialized cases. Saturated solutions, in tank crystallization, are allowed to cool in open tanks. After a period of time the mother liquor is drained and the crystals removed. Nucleation and size of crystals are difficult to control.{{citation needed|date=April 2016}} Typically, labor costs are very high.{{citation needed|date=April 2016}}
# ''Mixed-Suspension, Mixed-Product-Removal (MSMPR)'': MSMPR is used for much larger scale inorganic crystallization. MSMPR can crystalize solutions in a continuous manner.<ref>{{Cite web |title=MSMPR Crystallizer {{!}} Practical Solubility Science {{!}} Prof Steven Abbott |url=https://www.stevenabbott.co.uk/practical-solubility/MSMPR.php |access-date=2024-05-25 |website=www.stevenabbott.co.uk}}</ref>