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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 ...

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...

chemical bond

(Encyclopedia)chemical bond, mechanism whereby atoms combine to form molecules. There is a chemical bond between two atoms or groups of atoms when the forces acting between them are strong enough to lead to the for...

mass number

(Encyclopedia)mass number, often represented by the symbol A, the total number of nucleons (neutrons and protons) in the nucleus of an atom. All atoms of a chemical element have the same atomic number (number of pr...

fatty acid

(Encyclopedia)fatty acid, any of the organic carboxylic acids present in fats and oils as esters of glycerol. Molecular weights of fatty acids vary over a wide range. The carbon skeleton of any fatty acid is unbran...

Novoselov, Sir Konstantin Sergeevich

(Encyclopedia)Novoselov, Sir Konstantin Sergeevich, 1974–, Russian-British physicist, Ph.D. Univ. of Nijmegen, Netherlands, 2004. He has been a research associate at the Univ. of Manchester, England, since 2001. ...

formula, in chemistry

(Encyclopedia)formula, in chemistry, an expression showing the chemical composition of a compound. Formulas of compounds are used in writing the equations (see chemical equations) that represent chemical reactions....

Dalton, John

(Encyclopedia)Dalton, John dôlˈtən [key], 1766–1844, English scientist. He revived the atomic theory (see atom), which he formulated in the first volume of his New System of Chemical Philosophy (2 vol., 1808�...

Geim, Sir Andre Konstantinovich

(Encyclopedia)Geim, Sir Andre Konstantinovich, 1958–, Russian-born Dutch physicist, Ph.D. Russian Academy of Sciences, 1987. He was a professor at the Univ. of Nijmegen in the Netherlands from 1994 to 2001, when ...

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...