ubstances applied to inanimate bodies, whereas antiseptics, not so potent, are agents that kill microbes on living things.
..... Click the link for more information. and as an antiseptic (mercuric chloride); and in the manufacture of bleaching powder (chloride of lime), dyes, and explosives. Chlorinated hydrocarbons have been used extensively as pesticides; some examples are DDTDDT
or 2,2-bis(p-chlorophenyl)-1,1,1,-trichloroethane, chlorinated hydrocarbon compound used as an insecticide. First introduced during the 1940s, it killed insects that spread disease and fed on crops, and Swiss scientist Paul Müller was awarded the 1948 Nobel Prize
..... Click the link for more information. , dieldrin, aldrin, endrin, lindane, chlordane, and heptachlor. These compounds resist degradation and have become very troublesome environmental pollutants. Carbon tetrachloride and trichloroethylene are used as solvents. The FreonFreon
[trade name], any one of a special class of chemical compounds that are used as refrigerants, aerosol propellants, and solvents. These compounds are haloalkanes, i.e., halogen derivatives of saturated hydrocarbons (see alkane).
..... Click the link for more information. refrigerants are hydrocarbons that have been reacted with chlorine and fluorine. Chlorine is an important constituent of many poison gasespoison gas,
any of various gases sometimes used in warfare or riot control because of their poisonous or corrosive nature. These gases may be roughly grouped according to the portal of entry into the body and their physiological effects.
..... Click the link for more information. . It is used in such compounds as calomel, chloroformchloroform
, CHCl3, volatile, colorless, nonflammable liquid that has a sweetish taste and a somewhat pungent odor; it boils at 61.7°C;. It dissolves freely in ethanol and ether but does not mix with water.
..... Click the link for more information. , and chloral hydratechloral hydrate
, central nervous system depressant that is widely used as a hypnotic, or sleep-inducing drug. Chloral hydrate is the common ingredient, along with alcohol, in what are popularly known as knockout drops or Mickey Finns; the combination can induce acute
..... Click the link for more information. , which are used in medicine. It is also employed in the extraction of bromine from seawater. It is used in preparing some synthetic rubbers, in petroleum refining, and to prepare pure hydrochloric acid (see 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.
..... Click the link for more information. ).
Cl, a chemical element in Group VII of Mendeleev’s periodic system. Atomic number, 17; atomic weight, 35.453. A member of the halogen family.
Under normal conditions (0°C and 0.1 meganewton/m2, or 1 kilogram-force/cm2), chlorine is a yellowish green gas, with a pungent, irritating odor. It occurs naturally in the form of two stable isotopes: 35Cl (75.77 percent) and 37Cl (24.23 percent). A number of radioactive chlorine isotopes have been obtained artificially, with mass numbers 32, 33, 34, 36, 38, 39, and 40, which have a half-life of 0.31 sec, 2.5 sec, 1.56 sec, 3.1 × 105 yr, 37.3 min, 55.5 min, and 1.4 min, respectively. 36Cl and 38Cl are used as isotopic tracers.
History. Chlorine was first obtained in 1774 by K. Scheele by the reaction of hydrochloric acid with pyrolusite (manganese dioxide). However, it was only in 1810 that H. Davy established it as an element and named it chlorine (from Greek chloros, “yellowish green”). In 1813, J. L. Gay-Lussac proposed the French name chlore for this element from which the Russian name khlor is derived.
Distribution in nature. Chlorine is found in nature only as a component of compounds. The average content of chlorine in the earth’s crust (clarke) is 1.7 × 10–2 percent by weight. The average content in acidic igneous rocks, such as gran