yttrium

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yttrium

(ĭt`rēəm) [for Ytterby, a town in Sweden], metallic chemical element; symbol Y; at. no. 39; at. wt. 88.90585; m.p. about 1,522°C;; b.p. 3,338°C;; sp. gr. about 4.45; valence +3. Yttrium is a highly crystalline iron-gray metal. Usually considered a rare-earth metalrare-earth metals,
in chemistry, group of metals including those of the lanthanide series and actinide series and usually yttrium, sometimes scandium and thorium, and rarely zirconium. Promethium, which is not found in nature, is not usually considered a rare-earth metal.
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, it is found above lanthanum in Group 3 of the periodic tableperiodic table,
chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
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. Yttrium is fairly stable in air but oxidizes readily when heated. It reacts with water and mineral acids. The largest use of the element is as its oxide yttria, Y2O3, which is used in making red phosphors for color television picture tubes; it also has other uses. Yttrium metal has found some use alloyed in small amounts with other metals. Yttrium is not found uncombined in nature, but occurs in many minerals, e.g., gadolinite, euxenite, and xenotime. It is recovered commercially from monazite and bastnasite. In 1794, Johan Gadolin isolated impure yttria from the mineral gadolinite. In 1843, C. G. Mosander isolated pure yttria as well as two impure fractions that he called erbia and terbia. The metal was first isolated in 1828 by Friedrich Wöhler.

Yttrium

 

a chemical element in Group III of the Mendeleev periodic system. Atomic number, 39; atomic weight, 88.9059. One stable isotope, 89Y, exists in nature.

Yttrium, scandium, lanthanum, and lanthanides make up the rare earths, a group of elements that are very similar in chemical properties, occurrence in nature, and history of discovery.

Yttrium is a light metal, with a density of 4.472 g/cm3. Theisotope 89Y has a small capture cross section for thermal neu-trons (1.38 ×a 10-28m2, or 1.38 barns), so that the element can be used as a construction material in nuclear engineering. The high durability of relatively light yttrium-aluminum alloys makes them highly suitable for aircraft construction. Yttrium ferrites can be prepared from yttrium oxide, Y2003 (of very highpurity); these ferrites are used in radio electronics, hearing aids, and computer memory cells.

yttrium

[′i·trē·əm]
(chemistry)
A rare-earth metal, symbol Y, atomic number 39, atomic weight 88.9059; dark-gray, flammable (as powder), soluble in dilute acids and potassium hydroxide solution, and decomposes in water; melts at 1500°C, boils at 2927°C; used in alloys and nuclear technology and as a metal deoxidizer.

yttrium

a silvery metallic element occurring in monazite and gadolinite and used in various alloys, in lasers, and as a catalyst. Symbol: Y; atomic no.: 39; atomic wt.: 88.90585; valency: 3; relative density: 4.469; melting pt.: 1522?C; boiling pt.: 3338?C