Gadolinium

=**Gadolinium**=
 * Atomic Number:** 64
 * Atomic Weight:** 157.25
 * Melting Point:** 1586 K (1313°C or 2395°F)
 * Boiling Point:** 3546 K (3273°C or 5923°F)
 * Density:** 7.90 grams per cubic centimeter
 * Phase at Room Temperature:** Solid
 * Element Classification:** Metal
 * Period Number:** 6 **Group Number:** none **Group Name:** Lanthanide
 * What's in a name?** Named for the mineral **gadolinite** which was named after Johan Gadolin, a Finnish chemist.
 * Say what?** Gadolinium is pronounced as **GAD-oh-LIN-ee-em**.

Spectroscopic evidence for the existence of gadolinium was first observed by the Swiss chemist Jean Charles Galissard de Marignac in the minerals didymia and gadolinite ((Ce, La, Nd, Y)2FeBe2Si2O10) in 1880. Today, gadolinium is primarily obtained from the minerals monazite ((Ce, La, Th, Nd, Y)PO4) and bastnasite ((Ce,La,Y)CO3F). Gadolinium has the greatest ability to capture thermal neutrons of all known elements and can be used as control rods for nuclear reactors. Unfortunately, the two isotopes best suited for neutron capture, gadolinium-155 and gadolinium-157, are present in gadolinium in small amounts. As a result, gadolinium control rods quickly lose their effectiveness. Gadolinium can be combined with yttrium to form garnets that have applications in microwave technology. Gadolinium can be alloyed with iron, chromium and other metals to improve their workability and their resistance to high temperatures and oxidation. Gadolinium compounds are used to make phosphors for color televisions.
 * History and Uses:**
 * used for making gadolinium yttrium garnets which have microwave applications
 * gadolinium compounds are used for making phosphors for colour TV tubes
 * alloys
 * CD disks
 * superconductive properties
 * solutions of gadolinium compounds are used as intravenous contrasts to enhance images in patients undergoing MRI (magnetic resonance imaging)
 * Estimated Crustal Abundance:** 6.2 milligrams per kilogram
 * Estimated Oceanic Abundance:** 7×10-7 milligrams per liter
 * Number of Stable Isotopes:** 5
 * Ionization Energy:** 6.150 eV
 * Oxidation State:** +3

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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 [|Lecoq de Boisbaudran] in 1886. Gadolinium metal possesses unusual [|metallurgic] properties, with as little as 1% of gadolinium improving the workability and resistance of [|iron], [|chromium], and related [|alloys] to high temperatures and [|oxidation]. 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. Gd (III) salts have therefore been used as green phosphors in various applications. The Gd(III) ion occurring in water-soluble salts is quite toxic to mammals. However, [|chelated] Gd(III) compounds are far less toxic because they carry Gd(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 gadolinium ion itself, since Gd(III) carrier molecules associated with the disease differ.

History
Gadolinium is named from the mineral [|gadolinite], in turn named for [|Finnish] chemist and [|geologist] [|Johan Gadolin]. [|[1]] In 1880, [|Swiss] [|chemist] [|Jean Charles Galissard de Marignac] observed spectroscopic lines due to gadolinium in samples of [|didymium] and gadolinite, and separated from them " [|gadolinia] ," gadolinium oxide. Because he realized that gadolinia was the oxide of a new element, he is credited with discovery of gadolinium. [|French] chemist [|Paul Émile Lecoq de Boisbaudran] carried out the separation of gadolinium metal from the oxide in 1886.