water of crystallization

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wa·ter of crys·tal·li·za·tion

water of constitution that unites with certain salts and is essential to their arrangement in crystalline form; for example, CuSO4·5H2O.

wa·ter of crys·tal·li·za·tion

(waw'tĕr kris'tăl-ī-zā'shŭn)
Water of constitution that unites with certain salts and is essential to their arrangement in crystalline form, e.g., CuSO4·5H2O.


H2O, hydrogen combined with oxygen, forming a clear, tasteless, odorless fluid.
CAS # 7732-18-5

Water freezes at 32°F (0°C) and boils at 212°F (100°C). It is the principal chemical constituent of the body, composing approx. 65% of the body weight of an adult male and 55% of the adult female. It is distributed within the intracellular fluid and outside the cells in the extracellular fluid. Water is indispensable for metabolic activities within cells, being the medium in which chemical reactions usually take place. Outside of cells, it is the principal transporting agent of the body. The following properties of water are important to living organisms: it is an almost universal solvent; it is a medium in which acids, bases, and salts ionize, and the concentrations of these substances (electrolytes) are regulated by the body; it possesses a high specific heat and has a high latent heat of vaporization (important in regulating a constant body temperature); it possesses a high surface tension; and it is an important reacting agent and essential in all hydrolytic reactions.

Water is the principal constituent of all body fluids (blood, lymph, tissue fluid), secretions (saliva, gastric juice, bile, sweat), and excretory fluid (urine). Intake of water is determined principally by the sense of thirst. Excessive intake may lead to water intoxication; excessive loss to dehydration. Humans can survive for only a short time without water intake. The exact length of survival time varies with ambient temperature, moisture in available food, and amount of physical activity.

ammonia water

Ammonium hydroxide.

boiled rice water

The water remaining after rice has been cooked in it and removed; formerly used as an oral rehydration agent, esp. for children with diarrhea. Oral rehydration solutions are a better source of fluids and electrolytes and have replaced the use of boiled rice water for rehydration.

bound water

Intracellular water attached to organic molecules. It is not available for metabolic processes.

water of crystallization

Water of hydration.

deionized water

Water that has been passed through a substance that removes cations and anions present as contaminants. As ionic purity increases, so does the electrical resistance of the water.


Deionization is not synonymous with sterilization. It does not remove bacterial, fungal, or viral pathogens from water.

distilled water

Water purified by distillation. It is used in preparing pharmaceuticals.

fresh water

Water that contains a specified amount of solute, typically less than 1000 mg of solute per liter.

gray water

Wastewater that has been used in kitchens, laundries, sinks, showers, and tubs, but not toilets.

hard water

Water that contains dissolved salts of magnesium or calcium.

heavy water

D2O; an isotopic variety of water, esp. deuterium oxide, in which hydrogen has been displaced by its isotope, deuterium. Its properties differ from ordinary water in that heavy water has a higher freezing and boiling point and does not support life.

water of hydration

Water within the crystalline structure of an ionic compound that can be removed by heating or other means, leaving a pure salt.
Synonym: water of crystallization

water for injection

Distilled, sterilized water for parenteral use.

Javelle water

An aqueous solution of potassium or sodium hypochlorite used as a bleach and disinfectant.

mineral water

Water that contains sufficient inorganic salts to cause it to have therapeutic properties.

potable water

Water suitable for drinking. Drinking water should be free of disease-causing organisms and should contain only trace amounts of organic and/or inorganic chemicals.

purified water

Water that is filtered to be free of biological or chemical contaminants or is obtained by distillation or deionization.

pyrogen-free water

Water free of fever-producing proteins (bacteria and their metabolic products).
See: water for injection

rose water

A saturated aqueous solution of rose oil, used to impart agreeable odor to lotions.

seltzer water

1. Naturally occurring water with a high mineral and carbon dioxide content.
2. Soda water.

soda water

Hydrated carbon dioxide.
Synonym: seltzer water (2)

soft water

Water that contains very little, if any, dissolved salts of magnesium or calcium.