What is "gadolinium"

Gadolinium \Gad`o*lin"i*um\, n. [NL. See Gadolinite.] (Chem.) A rare earth metallic element of the Lanthanide series, with a characteristic spectrum, found associated with yttrium and other rare earth elements. Symbol, Gd; it has an atomic number of 64, an atomic weight of 157.25 (C=12.011), and a valence of +3.

metallic element, with element ending -ium + gadolinia, an earth named 1886 by J.C. Marginac in honor of Johan Gadolin (1760-1852), Finnish mineralogist and chemist, who in 1794 first began investigation of the earth (subsequently called gadolinite, 1802) which eventually yielded this element and several others.

n. A metallic chemical element (''symbol'' Gd) with an atomic number of 64.

n. a ductile silvery-white ductile ferromagnetic trivalent metallic element of the rare earth group [syn: Gd, atomic number 64]

Gadolinium is a chemical element with symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined (salt) form. Gadolinium was first detected spectroscopically in 1880 by de Marignac who separated its oxide and is credited with its discovery. It is named for gadolinite, one of the minerals in which it was found, in turn named for chemist Johan Gadolin. The metal was isolated by Paul Emile Lecoq de Boisbaudran in 1886.

Gadolinium metal possesses unusual metallurgic properties, to the extent that as little as 1% gadolinium can significantly improve the workability and resistance to high temperature oxidation of iron, chromium, and related alloys. Gadolinium as a metal or salt has exceptionally high absorption of neutrons and therefore is used for shielding in neutron radiography and in nuclear reactors. Like most rare earths, gadolinium forms trivalent ions which have fluorescent properties. Gadolinium(III) salts have therefore been used as green phosphors in various applications.

The gadolinium(III) ion occurring in water-soluble salts is quite toxic to mammals. However, chelated gadolinium(III) compounds are far less toxic because they carry gadolinium(III) through the kidneys and out of the body before the free ion can be released into tissue. Because of its paramagnetic properties, solutions of chelated organic gadolinium complexes are used as intravenously administered gadolinium-based MRI contrast agents in medical magnetic resonance imaging. However, in a small minority of patients with renal failure, at least four such agents have been associated with development of the rare nodular inflammatory disease nephrogenic systemic fibrosis. This is thought to be due to the gadolinium ion itself, since gadolinium(III) carrier molecules associated with the disease differ.