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(klōr`īd, klôr`–), chemical compound containing chlorine. Most chlorides are salts that are formed either by direct union of chlorine with a metal or by reaction of hydrochloric acid (a water solution of hydrogen chloridehydrogen chloride,
chemical compound, HCl, a colorless, poisonous gas with an unpleasant, acrid odor. It is very soluble in water and readily soluble in alcohol and ether. It fumes in moist air. It is not flammable, and the liquid is a poor conductor of electricity.
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) with a metal, a metal oxide, or an inorganic base. Chloride salts include sodium chloridesodium chloride,
NaCl, common salt. Properties

Sodium chloride is readily soluble in water and insoluble or only slightly soluble in most other liquids. It forms small, transparent, colorless to white cubic crystals.
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 (common salt), potassium chloridepotassium chloride,
chemical compound, KCl, a colorless or white, cubic, crystalline compound that closely resembles common salt (sodium chloride). It is soluble in water, alcohol, and alkalies.
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, calcium chloridecalcium chloride,
CaCl2, chemical compound that is crystalline, lumpy, or flaky, is usually white, and is very soluble in water. The anhydrous compound is hygroscopic; it rapidly absorbs water and is used to dry gases by passing them through it.
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, and ammonium chlorideammonium chloride
, chemical compound, NH4Cl, a white or colorless, odorless, water-soluble, cubic crystalline salt with a biting taste, commonly known as sal ammoniac.
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. Most chloride salts are readily soluble in water, but mercurous chloridemercurous chloride,
 mercury (I) chloride,
or calomel,
chemical compound, Hg2Cl2, a white crystalline powder, very slightly soluble in water.
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 (calomel) and silver chloridesilver chloride,
chemical compound, AgCl, a white cubic crystalline solid. It is nearly insoluble in water but is soluble in a water solution of ammonia, potassium cyanide, or sodium thiosulfate ("hypo").
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 are insoluble, and lead chloride is only slightly soluble. Some chlorides, e.g., antimony chloride and bismuth chloride, decompose in water, forming oxychlorides. Many metal chlorides can be melted without decomposition; two exceptions are the chlorides of gold and platinum. Most metal chlorides conduct electricity when fused or dissolved in water and can be decomposed by electrolysiselectrolysis
, passage of an electric current through a conducting solution or molten salt that is decomposed in the process. The Electrolytic Process

The electrolytic process requires that an electrolyte, an ionized solution or molten metallic salt, complete an
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 to chlorine gas and the metal. Chlorine forms compounds with the other halogens and with oxygen; when chlorine is the more electronegative element in the compound, the compound is called a chloride. Thus, compounds with bromine and iodine are bromine chloride, BrCl, and iodine chloride, ICI, but compounds with oxygen or fluorine (which are more electronegative than chlorine) are oxides (e.g., chlorine dioxide, ClO2) or fluorides (e.g., chlorine fluoride, ClF) respectively. Many organic compounds contain chlorine, as is indicated by common names such as carbon tetrachloride, methylene chloride, and methyl chloride. However, in the nomenclature system for organic chemistry adopted by the International Union of Pure and Applied Chemistry (IUPAC), the presence in a compound of chlorine bonded to a carbon atom is indicated by the prefix or infix chloro; thus, carbon tetrachloride is tetrachloromethane, methylene chloride is dichloromethane, and methyl chloride is chloromethane.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



any one of a group of compounds of chlorine with all elements possessing lower electronegativity, that is, with all metals and nonmetals except oxygen and fluorine. (The chlorides of nitrogen constitute another exception; they are named thus, although the electronegativity of nitrogen is greater than that of chorine.)

Metal chlorides (or salts of hydrochloric acid) are solids, most of which melt or vaporize without decomposition. Most are readily soluble in water except AgCl, CuCl, HgCl2, TlCl, and PbCl2, which are poorly soluble. The chlorides of alkali and alkaline-earth metals are neutral. Solutions of chlorides of other metals are acidic as a result of hydrolysis; for example, AlCl3 + 3H2O = Al(OH)3 + 3HCl.

Chlorides of nonmetals may be gases (HCl), liquids (PCl3), or solids (PCl5). Such compounds are hydrolyzed by water; for example, PCl5 + 4H2O = H3PO4 + 5HCl.

Sodium chloride, potassium chloride, magnesium chloride, and calcium chloride are common in nature (see).

For information on the properties, production, and uses of chlorides, seePOTASSIUM CHLORIDE; SODIUM CHLORIDE; MAGNESIUM CHLORIDE; CALCIUM CHLORIDE; and TITANIUM HALIDE.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


A compound which is derived from hydrochloric acid and contains the chlorine atom in the -1 oxidation state.
In general, any binary compound containing chloride.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


1. any salt of hydrochloric acid, containing the chloride ion Cl--
2. any compound containing a chlorine atom, such as methyl chloride (chloromethane), CH3Cl
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
In laboratory, AE technique is powerful for the study of localized corrosion and stress corrosion mechanisms of prestressing strand in the presence of chloride ions at high alkaline pH.
The chloride ion penetration depth was measured after 10, 20, 30 and 40 cycles of exposure period.
It should be emphasized that the amount of chloride ions remains constant in the lower chamber despite the water flow from the water container, because this water flow balances only the water that crosses the paint film to the upper chamber.
* If not, what is the level of carbonation and/or chloride ions?
where P is the content of free chloride ions in paste, %; C is the concentration of AgN[O.sub.3], mol/L; G is the weight of the paste sample, g; [V.sub.1] is the volume of water used to soak the sample, mL; [V.sub.2] is the volume of filtrate used for measurement, mL; and [V.sub.3] is the volume of consumption of silver nitrate solution, mL.
(3) The ratio of [Fe.sup.3+]/[Fe.sup.2+] increases as chloride ions increase or carbonization increases.
And salt contains ions --many more positively charged sodium ions and negatively charged chloride ions than those in freshwater.
Gorilla Grout is free of chloride ions or other additives known to cause oxidation and deterioration of concrete or base plates, or structural steel.
The mechanisms of these free radical reactions with TCNM were investigated, using [sup.60]Co gamma irradiation at various absorbed doses, measuring the disappearance of TCNM and the appearance of the product nitrate and chloride ions [21].
In addition to increasing the efflux of chloride ions through a protein channel called CFTR, it weakens cell junctions to allow a rapid outflow of counterbalancing sodium ions and water between the cells.
10 issue of Science, MIT researchers report that charged molecules, such as the sodium and chloride ions that form when salt is dissolved in water, can not only flow rapidly through carbon nanotubes, but also can, under some conditions, do so one at a time, like people taking turns crossing a bridge.