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In some contexts, water of crystallization is the total mass of water in a substance at a given temperature and is mostly present in a definite (stoichiometric) ratio. Classically, "water of crystallization" refers to water that is found in the crystalline framework of a metal complex or a salt, which is not directly bonded to the metal cation.
One example is the pair [CrCl(H 2 O) 5]Cl 2 •H 2 O and [Cr(H 2 O) 6]Cl 3. [1] The former has one water of crystallization but the latter does not. Another example is the pair of titanium(III) chlorides, [Ti(H 2 O) 6]Cl 3 and [Ti(H 2 O) 4 Cl 2]Cl(H 2 O) 2. The former is violet and the latter, with two molecules of water of crystallization, is ...
Another example is chloral hydrate, CCl 3 −CH(OH) 2, which can be formed by reaction of water with chloral, CCl 3 −CH=O. Many organic molecules, as well as inorganic molecules, form crystals that incorporate water into the crystalline structure without chemical alteration of the organic molecule ( water of crystallization ).
An example of this crystallization process is the production of Glauber's salt, a crystalline form of sodium sulfate. In the diagram, where equilibrium temperature is on the x-axis and equilibrium concentration (as mass percent of solute in saturated solution) in y-axis , it is clear that sulfate solubility quickly decreases below 32.5 °C.
Oil droplets in pastis mixed with water grow by Ostwald ripening. One example of Ostwald ripening is the re-crystallization of water within ice cream which gives old ice cream a gritty, crunchy texture. Larger ice crystals grow at the expense of smaller ones within the ice cream, creating a coarser texture. [15]
An example of such texture, related to fractioned crystallization, is intergranular (also known as intercumulus) textures that develop wherever a mineral crystallizes later than the surrounding matrix, hence filling the left-over interstitial space. Various oxides of chromium, iron and titanium show such textures, such as intergranular chromite ...
Phase transitions (phase changes) that help describe polymorphism include polymorphic transitions as well as melting and vaporization transitions. According to IUPAC, a polymorphic transition is "A reversible transition of a solid crystalline phase at a certain temperature and pressure (the inversion point) to another phase of the same chemical composition with a different crystal structure."
A colloidal crystal is an ordered array of colloidal particles and fine grained materials analogous to a standard crystal whose repeating subunits are atoms or molecules. [1] A natural example of this phenomenon can be found in the gem opal, where spheres of silica assume a close-packed locally periodic structure under moderate compression.