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YY at. wt. 88.905 at. no. 39 m.p. 1523±8°C b.p. 3337°C sp. gr. 4.457 valence 3.
| SHELL | K | L | M | N | O | P | Q |
| SUB SHELL | He | Neon | Argon | Krypton | Xenon | Radon | Eka-radon |
| 1s | 2s 2p | 3s 3p | 3d 4s 4p | 4d 5s 5p | 4f 5d 6s 6p | 5f 6d 7s 7p | |
| Yttrium | 1s22s22p63s23p63d104s24p64d15s2 | ||||||
| Symbol | 2D3/2 | ||||||
Yttria, which is an earth containing yttrium, was discovered by Gadolin in 1794. Ytterby is the site of a quarry which yielded many unusual minerals containing rare earths and other elements. This small town, near Stockholm, bears the honor of giving names to erbium, terbium, and ytterbium, as well as yttrium. In 1843 Mosander showed that yttria could be resolved into the earths of three elements. The name yttria was reserved for the most basic one; the others were named erbia and terbia. Yttrium occurs in nearly all of the rare-earth minerals. Preliminary analysis of lunar rock samples obtained during the Apollo II mission showed a relatively high yttrium content. It is recovered commercially from monazite sand, which contains about 3 %, and from bastnashe, which contains about 0.2 %. Wdhler obtained the impure element in 1828 by reduction of the anhydrous chloride with potas- sium. The metal is now produced commercially by reduction of the fluoride with calcium metal. It can also be prepared by other techniques. Yttrium has a silvery metallic luster and is relatively stable in air. Turnings of the metal, how- ever, ignite in air if their temperature exceeds 4000C, and finely divided yttrium is very unstable in air. Yttrium oxide is one of the most important compounds of yttrium and accounts for the largest use. It is widely used in making YVO4 : Europium, and Y203 Europium phosphors to give the red color in color television tubes. Many hundreds of thousands of pounds are now used in this application. Yttrium oxide also is used to produce yttrium-iron-garnets, which are very effective microwave filters. Yttrium iron, aluminum, and gadolinium garnets, with formulas such as Y3Fe5O12 and Y3A15012, have interesting magnetic proper- ties. Yttrium iron garnet is also exceptionally efficient as both a transmitter and transducer of acoustic energy. Small amounts of yttrium (0.1 to 0.2%) can be used to reduce the grain size in chromium, molybdenum, zirconium, and titanium, and to increase strength of aluminum and magnesium alloys. Alloys with other useful properties can be obtained by using yttrium as an additive. The metal can be used as a deoxidizer for vanadium and other nonferrous metals. The metal has a low cross section for nuclear cap- ture. Y90, one of the isotopes of yttrium, exists in equili- brium with its parent 5r90, a product of atomic explosions. Yttrium has been considered for use as a nodulizer for producing nodular cast iron, in which the graphite forms compact nodules instead of the usual flakes. Such iron has increased ductility. Yttrium is also finding application in laser systems and as a catalyst for ethylene polymerization. It has also potential use in ceramic and glass formulas as the oxide has a high melting point and imparts shock resistance and low expansion characteristics to glass. Natural yttrium contains but one isotope, y89. Twenty other unstable nuclides and isomers have been characterized. Yttrium metal of 99+ % purity is commercially available at a cost of about $1/gm or $200/lb.
© 1999 F. Davies
Delphi O.E.M. Co.
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