What is "water of crystallization"

Water \Wa"ter\ (w[add]"t[~e]r), n. [AS. w[ae]ter; akin to OS. watar, OFries. wetir, weter, LG. & D. water, G. wasser, OHG. wazzar, Icel. vatn, Sw. vatten, Dan. vand, Goth. wat[=o], O. Slav. & Russ. voda, Gr. 'y`dwr, Skr. udan water, ud to wet, and perhaps to L. unda wave. [root]137. Cf. Dropsy, Hydra, Otter, Wet, Whisky.]

1. The fluid which descends from the clouds in rain, and which forms rivers, lakes, seas, etc. ``We will drink water.''
   --Shak. ``Powers of fire, air, water, and earth.''
   --Milton.

   Note: Pure water consists of hydrogen and oxygen, H2O, and is a colorless, odorless, tasteless, transparent liquid, which is very slightly compressible. At its maximum density, 39[deg] Fahr. or 4[deg] C., it is the standard for specific gravities, one cubic centimeter weighing one gram. It freezes at 32[deg] Fahr. or 0[deg] C. and boils at 212[deg] Fahr. or 100[deg] C. (see Ice, Steam). It is the most important natural solvent, and is frequently impregnated with foreign matter which is mostly removed by distillation; hence, rain water is nearly pure. It is an important ingredient in the tissue of animals and plants, the human body containing about two thirds its weight of water.

2. A body of water, standing or flowing; a lake, river, or other collection of water.

   Remembering he had passed over a small water a poor scholar when first coming to the university, he kneeled.
   --Fuller.

3. Any liquid secretion, humor, or the like, resembling water; esp., the urine.

4. (Pharm.) A solution in water of a gaseous or readily volatile substance; as, ammonia water.
   --U. S. Pharm.

5. The limpidity and luster of a precious stone, especially a diamond; as, a diamond of the first water, that is, perfectly pure and transparent. Hence, of the first water, that is, of the first excellence.

6. A wavy, lustrous pattern or decoration such as is imparted to linen, silk, metals, etc. See Water, v. t., 3, Damask, v. t., and Damaskeen.

7. An addition to the shares representing the capital of a stock company so that the aggregate par value of the shares is increased while their value for investment is diminished, or ``diluted.'' [Brokers' Cant] Note: Water is often used adjectively and in the formation of many self-explaining compounds; as, water drainage; water gauge, or water-gauge; waterfowl, water-fowl, or water fowl; water-beaten; water-borne, water-circled, water-girdled, water-rocked, etc. Hard water. See under Hard. Inch of water, a unit of measure of quantity of water, being the quantity which will flow through an orifice one inch square, or a circular orifice one inch in diameter, in a vertical surface, under a stated constant head; also called miner's inch, and water inch. The shape of the orifice and the head vary in different localities. In the Western United States, for hydraulic mining, the standard aperture is square and the head from 4 to 9 inches above its center. In Europe, for experimental hydraulics, the orifice is usually round and the head from 1/2 of an inch to 1 inch above its top. Mineral water, waters which are so impregnated with foreign ingredients, such as gaseous, sulphureous, and saline substances, as to give them medicinal properties, or a particular flavor or temperature. Soft water, water not impregnated with lime or mineral salts. To hold water. See under Hold, v. t. To keep one's head above water, to keep afloat; fig., to avoid failure or sinking in the struggles of life. To make water.

   1. To pass urine.
      --Swift.

   2. (Naut.) To admit water; to leak.

      Water of crystallization (Chem.), the water combined with many salts in their crystalline form. This water is loosely, but, nevertheless, chemically, combined, for it is held in fixed and definite amount for each substance containing it. Thus, while pure copper sulphate, CuSO4, is a white amorphous substance, blue vitriol, the crystallized form, CuSO4.5H2O, contains five molecules of water of crystallization.

      Water on the brain (Med.), hydrocephalus.

      Water on the chest (Med.), hydrothorax.

      Note: Other phrases, in which water occurs as the first element, will be found in alphabetical order in the Vocabulary.

alt. (context chemistry English) The water present in the crystals of the salts of certain metals; it is weakly bound by electrostatic forces and may normally be removed by heating. n. (context chemistry English) The water present in the crystals of the salts of certain metals; it is weakly bound by electrostatic forces and may normally be removed by heating.

n. the water present in hydrated compounds [syn: water of crystallisation, water of hydration]

In chemistry, water of crystallization or water of hydration or crystallization water is water that occurs inside crystals. Water is often necessary for the formation of crystals. In some contexts, water of crystallization is the total weight 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

sulfate.jpg|Hydrated copper(II) sulfate is bright blue. sulfate anhydrous.jpg|Anhydrous copper(II) sulfate is white.

Upon crystallization from water or moist solvents, many compounds incorporate water molecules in their crystalline frameworks. Water of crystallization can generally be removed by heating a sample but the crystalline properties are often lost.

Compared to inorganic salts, proteins crystallize with unusually large amounts of water in the crystal lattice. A water content of 50% is not uncommon.