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organometallic chemistry

(Encyclopedia)organometallic chemistry, the reactions and use of a class of compounds (R-M) that contain a covalent bond between carbon and metal. They are prepared either by direct reaction of the metal with an or...

electronegativity

(Encyclopedia)electronegativity ĭlĕkˌtrōnĕgətĭvˈətē [key], 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...

Grignard reagent

(Encyclopedia)Grignard reagent grēnyärdˈ rēāˈjənt [key], any of an important class of extremely reactive chemical compounds used in the synthesis of hydrocarbons, alcohols, carboxylic acids, and other compou...

carboxyl group

(Encyclopedia)carboxyl group kärbŏkˈsĭl [key], in chemistry, functional group that consists of a carbon atom joined to an oxygen atom by a double bond and to a hydroxyl group, OH, by a single bond. Carboxylic a...

Living Theater

(Encyclopedia)Living Theater: see drama, Western; Beck, Julian. ...

debenture

(Encyclopedia)debenture dəbĕnˈchər [key], document acknowledging indebtedness. In Great Britain a debenture is practically the same as a bond, and debenture stock is similar to preferred stock. In the United St...

formyl group

(Encyclopedia)formyl group fôrˈmĭl [key], in chemistry, functional group that consists of a carbonyl group joined by a single bond to a hydrogen atom. Aldehydes are compounds that contain a formyl group joined b...

hydroxyl group

(Encyclopedia)hydroxyl group hīdrŏkˈsĭl [key], 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 ...

Harvard College Observatory

(Encyclopedia)Harvard College Observatory, astronomical observatory located in Cambridge, Mass., operated by Harvard (Harvard College at the time of the observatory's founding in 1839). Its equipment includes a 61-...

Eutropius, Roman historian

(Encyclopedia)Eutropius yo͞otrōˈpēəs [key], fl. 4th cent. a.d., Roman historian, a protégé of the emperors Julian and Valens. His Breviarium ab urbe condita (10 books) is a summary of Roman history. ...