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cyano group

(Encyclopedia)cyano group sīˈənō, sī-ănˈō [key], in chemistry, functional group that consists of a carbon atom joined to a nitrogen atom by a triple bond; it can be joined to an atom or another group by a s...

saturation, of an organic compound

(Encyclopedia)saturation, of an organic compound, condition occurring when its molecules contain no double or triple bonds and thus cannot undergo addition reactions. For example, ethane (H3C–CH3) is a saturated ...

complex ion

(Encyclopedia)complex ion, charged molecular aggregate (see ion), consisting of a metallic atom or ion to which is attached one or more electron-donating molecules. In some complex ions, such as sulfate, SO4−2, t...

valence, in chemistry

(Encyclopedia)valence, combining capacity of an atom expressed as the number of single bonds the atom can form or the number of electrons an element gives up or accepts when reacting to form a compound. Atoms are c...

welding

(Encyclopedia)welding, process for joining separate pieces of metal in a continuous metallic bond. Cold-pressure welding is accomplished by the application of high pressure at room temperature; forge welding (forgi...

Horsley, Sir Victor Alexander Haden

(Encyclopedia)Horsley, Sir Victor Alexander Haden, 1857–1916, English surgeon and neurologist. A specialist in surgery of the endocrine glands and the nervous system, he devised a noted operation for spinal-cord ...

Hyperion, in astronomy

(Encyclopedia)Hyperion hīpērˈēən [key], in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn VII (or S7), Hyperion is the largest highly irregular (nonspherical) body in...

couvade

(Encyclopedia)couvade ko͞ovädˈ [key], imitation by the father of many of the concomitants of childbirth, at the time of his wife's parturition. The father may retire into seclusion as well as observe various tab...

Head, Sir Edmund Walker

(Encyclopedia)Head, Sir Edmund Walker, 1805–68, British governor-general of Canada (1854–61), cousin of Sir Francis Bond Head. An Oxford scholar and tutor, he published several books. His success as lieutenant ...

peptide

(Encyclopedia)peptide, organic compound composed of amino acids linked together chemically by peptide bonds. The peptide bond always involves a single covalent link between the α-carboxyl (oxygen-bearing carbon) o...