yttrium

yttrium (ĭt`rēəm) [for Ytterby, a town in Sweden], metallic chemical element; symbol Y; at. no. 39; at. wt. 88.9059; 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 metal, it is found above lanthanum in Group 3 of the periodic table. 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 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

---

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.