Yttrium - Misplaced Pages

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Yttrium (Template:PronEng), is a chemical element that has the symbol Y and atomic number 39. A silvery metallic transition metal, yttrium is common in rare-earth minerals and two of its compounds are used to make the red color phosphors in cathode ray tube displays, such as those used for televisions.

Characteristics

Yttrium is a silver-metallic, lustrous rare earth metal that is relatively stable in air. When yttrium is finely divided, it is very unstable in air. Shavings or turnings of the metal can ignite in air when they exceed 400 °C. The metal has a low neutron cross-section for nuclear capture.

Yttrium chemically resembles the lanthanides, and can appear to gain a slight pink lustre on exposure to light. The common oxidation state of yttrium is +3.

Applications

Yttrium(III) oxide is the most important yttrium compound and is widely used to make YV O₄:Eu and Y₂O₃:Eu phosphors that give the red color in color television picture tubes. Other uses:

Yttrium oxide is also used to make yttrium iron garnets which are very effective microwave filters.
Yttrium iron, aluminium, and gadolinium garnets (e.g. Y₃Fe₅O₁₂ and Y₃Al₅O₁₂) have interesting magnetic properties. Yttrium iron garnet is very efficient as an acoustic energy transmitter and transducer. Yttrium aluminium garnet has a hardness of 8.5 and is also used as a gemstone (simulated diamond).
Small amounts of the element (0.1 to 0.2%) have been used to reduce grain size of chromium, molybdenum, titanium, and zirconium. It is also used to increase the strength of aluminium and magnesium alloys.
Used as a catalyst for ethylene polymerization.
Yttrium aluminium garnet, Y₂O₃, yttrium lithium fluoride, and yttrium vanadate are used in combination with dopants such as neodymium, erbium, ytterbium in near-infrared lasers. Both crystals and ceramics are used.
It is used on the electrodes of some high-performance spark plugs.
It can be used to deoxidize vanadium and other non-ferrous metals.
Yttrium is also used in the manufacture of gas mantles for propane lanterns, as a replacement for thorium, which is slightly radioactive.
Cerium-doped yttrium aluminium garnet (YAG:Ce) crystals are used as phosphors to make white LEDs.

Yttrium was used as a "secret" element in a YBCO superconductor developed at the University of Houston, YBaCuO. This superconductor operated above 90K, notable because this is above liquid nitrogen's boiling point (77.1K). (Y_1.2Ba_0.8CuO₄). The matter created was a multi-crystal multi-phase mineral, which was black and green.
Yttrium has been studied for possible use as a nodulizer in the making of nodular cast iron which has increased ductility (the graphite forms compact nodules instead of flakes to form nodular cast iron). Potentially, yttrium can be used in ceramic and glass formulas, since yttrium oxide has a high melting point and imparts shock resistance and low thermal expansion characteristics to glass.
Yttrium oxide is used to stabilize the cubic form of zirconia, for use in jewelry, etc.
Yttria (yttrium(III) oxide) is used as a sintering additive in the production of porous silicon nitride.
The radioactive isotope Yttrium-90 is used for treatment of various cancers, including lymphoma, leukemia, ovarian, colorectal, pancreatic, and bone cancers.

History

In 1787, Karl Axel Arrhenius found a heavy black rock, which he believed to be a previously unknown tungsten ore, in a quarry near Ytterby, Sweden. He brought the specimen to Johan Gadolin at the University of Åbo who, in 1794, announced that the rock contained a new "earth" which he named yttria, which was actually yttrium oxide. Yttrium was first isolated in 1828 when Friedrich Wöhler heated yttrium chloride with potassium. The yttrium oxide also had traces of other previously unknown substances: erbium oxide and terbium oxide, isolated in 1843 by Carl Gustav Mosander, and ytterbium oxide, isolated in 1878 by Jean Charles Galissard de Marignac. All four of these new elements were named for Ytterby, the village in which they were discovered.

Occurrence

Due to the lanthanide contraction, ytrrium, which is trivalent, is of similar ionic size to dysprosium and its lanthanide neighbors. Due to the relatively gradual decrease in ionic size with increasing atomic number, the rare earth elements have always been difficult to separate. Even with eons of geological time, geochemical separation of the lanthanides has only rarely progressed much farther than a broad separation between light versus heavy lanthanides, otherwise known as the cerium and yttrium earths. This geochemical divide is reflected in the first two rare earths that were discovered, yttria in 1794 and ceria in 1803. As originally found, each comprised the entire mixture of the associated earths. Rare earth minerals, as found, usually are dominated by one group or the other, depending upon which size-range best fits the structural lattice. Thus, among the anhydrous rare earth phosphates, it is the tetragonal mineral xenotime that incorporates yttrium and the yttrium earths, whereas the monoclinic monazite phase incorporates cerium and the cerium earths preferentially. The smaller size of the yttrium group allows it a greater solid solubility in the rock-forming minerals that comprise the earth's mantle, and thus yttrium and the yttrium earths show less enrichment in the earth's crust, relative to chondritic abundance, than does cerium and the cerium earths. This has economic consequences: large orebodies of the cerium earths are known around the world, and are being actively exploited. Corresponding orebodies for yttrium tend to be rarer, smaller, and less concentrated. Most of the current supply of yttrium originates in the "ion adsorption clay" ores of Southern China. Some versions of these provide concentrates containing about 65% yttrium oxide, with the heavy lanthanides being present in ratios reflecting the Oddo-Harkins rule: even-numbered heavy lanthanides at abundances of about 5% each, and odd-numbered lanthanides at abundances of about 1% each. Similar compositions are found in xenotime or gadolinite.

Well-known minerals that contain yttrium include gadolinite, xenotime, samarskite, euxenite, fergusonite, yttrotantalite, yttrotungstite, yttrofluorite (a variety of fluorite), thalenite, yttrialite. Small amounts occur in zircon, which derives its typical yellow fluorescence from some of the accompanying heavy lanthanides. The zirconium mineral eudialyte, such as is found in southern Greenland, also contains small but potentially useful amounts of yttrium. Of the above yttrium minerals, most played a part in providing research quantities of lanthanides during the discovery days. Xenotime is occasionally recovered as a byproduct of heavy sand processing, but has never been nearly as abundant as the similarly recovered monazite (which typically contains a few percent of yttrium). Uranium ores processed in Ontario have occasionally yielded yttrium as a byproduct.

Isotopes

Y is both the only stable isotope and the only naturally occurring isotope of yttrium. 32 artificial isotopes have been synthesized, ranging in atomic mass from 76 to 108. The least stable of these is Y with a half-life of 500 ns, and the most stable is Y with a half-life of 106.65 days. Yttrium usotopes with masses at or below 88 decay primarily by positron emission, while those with masses at or above 90 decay primarily by electron emission. Isotopes with masses at or above 97 are also known to have minor decay paths of β− delayed neutron emission.

Precautions

Yttrium has no known biological role, though it tends to concentrate in the liver and bones. There is normally as little as .5 milligrams found within the entire human body. Yttrium can be found in edible plants in concentrations between 20 ppm and 100 ppm. Yttrium compounds which are soluble in water are considered toxic, while insoluble compounds are non-toxic.

Notes

Sound file - pronunciation
^ Lide, David R., ed. (2007–2008), "Zirconium", CRC Handbook of Chemistry and Physics, vol. 4, New York: CRC Press, p. 41, 978-0-8493-0488-0
J. Kong (2005). "9.2-W diode-pumped Yb:Y₂O₃ ceramic laser". Applied Physics Letters. 86: 116. doi:10.1063/1.1914958. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
M.Tokurakawa (2007). "Diode-pumped 188 fs mode-locked Yb:Y₂O₃ ceramic laser". Appl.Phys.Lett. 90: 071101. doi:10.1063/1.2476385. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Emsley, John (2001). Nature's Building Blocks. Oxford: Oxford University Press. pp. 495–498. ISBN 0-19-850341-5.
Audi, G. (2003). "Nubase2003 Evaluation of Nuclear and Decay Properties". Nuclear Physics A. 729. Atomic Mass Data Center: 3–128. doi:10.1016/j.nuclphysa.2003.11.001.

External links

Periodic table

	1	2															3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
1	H																															He
2	Li	Be																									B	C	N	O	F	Ne
3	Na	Mg																									Al	Si	P	S	Cl	Ar
4	K	Ca															Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn	Ga	Ge	As	Se	Br	Kr
5	Rb	Sr															Y	Zr	Nb	Mo	Tc	Ru	Rh	Pd	Ag	Cd	In	Sn	Sb	Te	I	Xe
6	Cs	Ba	La	Ce	Pr	Nd	Pm	Sm	Eu	Gd	Tb	Dy	Ho	Er	Tm	Yb	Lu	Hf	Ta	W	Re	Os	Ir	Pt	Au	Hg	Tl	Pb	Bi	Po	At	Rn
7	Fr	Ra	Ac	Th	Pa	U	Np	Pu	Am	Cm	Bk	Cf	Es	Fm	Md	No	Lr	Rf	Db	Sg	Bh	Hs	Mt	Ds	Rg	Cn	Nh	Fl	Mc	Lv	Ts	Og

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