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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 ...
"Nickel dichloride hexahydrate" consists of the chloride complex trans-[NiCl 2 (H 2 O) 4 plus water of crystallization. As indicated in the table below, many hydrates of metal chlorides are molecular complexes. [78] [79] These compounds are often important commercial sources of transition metal chlorides. Several hydrated metal chlorides are ...
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).
A stick made of another inert substance such as a magnesia stick (MgO) may also be used. It is then dipped into powdered borax and held in the hottest part of the flame where it swells up as it loses its water of crystallization and then shrinks, forming a colourless, transparent glass-like bead (a mixture of sodium metaborate and boric anhydride).
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]
In chemistry, fractional crystallization is a stage-wise separation technique that relies on the liquid–solid phase change. This technique fractionates via differences in crystallization temperature and enables the purification of multi-component mixtures, as long as none of the constituents can act as solvents to the others. Due to the high ...
Although KF is a destructive analysis, the sample quantity is small and is typically limited by the accuracy of weighing. For example, in order to obtain an accuracy of 1% using a scale with the typical accuracy of 0.2 mg, the sample must contain 20 mg water, which is e.g. 200 mg for a sample with 10% water.