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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 ...
Cold water extraction (also called CWE) is the process whereby a substance is extracted from a mixture via cold water. It is a type of fractional crystallization . The process generally involves taking a mixture of substances, dissolving them in warm water, and then rapidly cooling the mixture.
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).
Some mineral structures, for example, montmorillonite, are capable of including a variable amount of water without significant change to the mineral structure. [citation needed] Hydration is the mechanism by which hydraulic binders such as Portland cement develop strength. A hydraulic binder is a material that can set and harden submerged in ...
If water is cooled at a rate on the order of 10 6 K/s, the crystal nucleation can be avoided and water becomes a glass—that is, an amorphous (non-crystalline) solid. Its glass transition temperature is much colder and harder to determine, but studies estimate it at about 136 K (−137 °C; −215 °F). [ 9 ]
Hydrothermal synthesis can be defined as a method of synthesis of single crystals that depends on the solubility of minerals in hot water under high pressure. The crystal growth is performed in an apparatus consisting of a steel pressure vessel called an autoclave, in which a nutrient is supplied along with water. A temperature gradient is ...