carboxyl group

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carboxyl group

(kärbŏk`sĭl), in chemistry, functional groupfunctional group,
in organic chemistry, group of atoms within a molecule that is responsible for certain properties of the molecule and reactions in which it takes part. Organic compounds are frequently classified according to the functional group or groups they contain.
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 that consists of a carbon atom joined to an oxygen atom by a double bond and to a hydroxyl grouphydroxyl group
, in chemistry, functional group that consists of an oxygen atom joined by a single bond to a hydrogen atom. An alcohol is formed when a hydroxyl group is joined by a single bond to an alkyl group or aryl group.
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, OH, by a single bond. Carboxylic acids are compounds whose molecules contain a carboxyl group that is joined to a hydrogen atom, an alkyl groupalkyl group
, in chemistry, group of carbon and hydrogen atoms derived from an alkane molecule by removing one hydrogen atom (see radical). The name of the alkyl group is derived from the name of its alkane by replacing the -ane suffix with -yl, e.g.
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, or an aryl grouparyl group
, in chemistry, group of atoms derived from benzene or from a benzene derivative by removing one hydrogen that is bonded to the benzene ring (see radical). The simplest aryl group is phenyl, C6H5 ; it is derived from benzene.
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 by a single bond to its carbon atom. Dicarboxylic acids, compounds that contain two carboxyl groups, are important in a number of industrial processes. The four main types of reactions of carboxylic acids are chiefly due to either the weak acidity of the hydroxyl hydrogen or to the difference in electronegativityelectronegativity
, in chemistry, tendency for an atom to attract a pair of electrons that it shares with another atom (see chemical bond). For example, the molecule hydrogen chloride, HCl, consists of a hydrogen atom, H, and a chlorine atom, Cl, sharing a pair of electrons.
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 between carbon and oxygen. One type involves cleavage of the hydroxyl oxygen-hydrogen bond, e.g., reaction with an alcohol to form an esterester,
any one of a group of organic compounds with general formula RCO2R′ (where R and R′ are alkyl groups or aryl groups) that are formed by the reaction between an alcohol and an acid.
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 or reaction with an alkali to form a water-soluble salt. A second type involves addition of an electron-rich species to the electron-deficient carbon atom of the carboxyl group. A third type is characterized by the joining of a carbon atom directly to the carboxyl group. A fourth type involves the loss of carbon dioxide (decarboxylation). The second and third types are similar to reactions of the carbonyl groupcarbonyl group
, in chemistry, functional group that consists of an oxygen atom joined by a double bond to a carbon atom. The carbon atom is joined to the remainder of the molecule by two single bonds or one double bond.
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; the carboxyl group may be thought of as a carbonyl group joined to a hydroxyl group.

carboxyl group

[kär′bäk·səl ‚grüp]
(organic chemistry)

carboxyl group

, radical
the monovalent group --COOH, consisting of a carbonyl group bound to a hydroxyl group: the functional group in organic acids