Hydrate

Hydrates are compounds formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts. (If the water is heavy water, where the hydrogen consists of the isotope deuterium, then the term deuterate may be used in place of hydrate.)

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These substances do not contain water as such, but have their constituents (hydrogen, oxygen, hydroxyl) so arranged that water may be eliminated. Hence, hydrates are derivatives of, or compounds with, hydroxyl.

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Such a substance is considered to be anhydrous when it is not in such a union with water.

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The notation of anhydrous compound, where n is the number of water molecules per molecule of anhydrous salt, is commonly used to show that a salt is hydrated. The n is usually a low integer, though it is possible for fractional values to exist.

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Examples include borax, chloral hydrate, clathrate hydrates (a class of hydrates of gases), and chalcanthite.

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Water: :This article focuses on water as it is experienced in everyday life. See water (molecule) for information on the chemical and physical properties of pure water (H2O, hydrogen oxide)....

Salt: : This article is about the general chemical term salt. For the everyday meaning, see edible salt or its main ingredient, sodium chloride. For other meanings of the word salt, see salt (disambiguation)....

Heavy water: Heavy water is deuterium oxide, or D2O or 2H2O. It is chemically the same as normal water, H2O, but the hydrogen atoms are of the heavy isotope deuterium, in which the nucleus contains a neutron in addition to the proton found in the nucleus of any hydrogen atom. Gilbert Newton Lewis isolated the fi...