In 1787, Carl Axel Arrhenius found a new mineral near Ytterby in Sweden and named it ytterbite, after the village. Johan Gadolin discovered yttrium's oxide in Arrhenius' sample in 1789, and Anders Gustaf Ekeberg named the new oxide yttria. Elemental yttrium was first isolated in 1828 by Friedrich Wöhler.
The most important use of yttrium compounds is in making phosphors, such as the red ones used in television cathode ray tube displays and in LEDs. Other uses include the production of electrodes, electrolytes, electronic filters, lasers and superconductors; various medical applications; and as traces in various materials to enhance their properties. Yttrium has no known biological role. Exposure to yttrium compounds can cause lung disease in humans.
The pure element is relatively stable in air in bulk form, due to passivation resulting from the formation of a protective oxide film on its surface. This film can reach a thickness of 10 µm when yttrium is heated to 750 °C in water vapor. When finely divided, however, yttrium is very unstable in air; shavings or turnings of the metal can ignite in air at temperatures exceeding 400 °C. Yttrium nitride (YN) is formed when the metal is heated to 1,000 °C in nitrogen.
Chemically, yttrium resembles these elements more closely than its neighbor in the periodic table, scandium, and if its physical properties were plotted against atomic number then it would have an apparent number of 64.5 to 67.5, placing it between the lanthanoids gadolinium and erbium.
It often also falls in the same range for reaction order, resembling terbium and dysprosium at its chemical reactivity. Yttrium is so close in size to the so-called 'Yttrium group' of heavy lanthanoid ions that in solution, it behaves as if it were one of them.
One of the few notable differences between the chemistry of yttrium and that of the lanthanoids is that yttrium is almost exclusively trivalent, whereas about half of the lanthanoids have valences other than three.
Yttrium forms a water-insoluble fluoride, hydroxide, and oxalate, but its bromide, chloride, iodide, nitrate and sulfate are all soluble in water. The Y3+ ion is colorless in solution because of the absence of d and f electron shells.
With halogens, yttrium forms trihalides such as yttrium(III) fluoride yttrium(III) chloride yttrium(III) bromide at temperatures above roughly 200 °C. Similarly, carbon, phosphorus, selenium, silicon and sulfur all form binary compounds with yttrium at elevated temperatures.
Organoyttrium chemistry is the study of compounds containing carbon–yttrium bonds. A few of these are known to have yttrium in the oxidation state 0. (The +2 state has been observed in chloride melts, and +1 in oxide clusters in the gas phase.) Some trimerization reactions were observed by using organoyttrium compounds as catalysts. These compounds use as a starting material, which in turn is obtained from and concentrated hydrochloric acid and ammonium chloride.
Hapticity is how a group of contiguous atoms of a ligand are coordinated to a central atom; it is indicated by the Greek character eta, η. Yttrium complexes were the first examples of complexes where carboranyl ligands were bound to a d0-metal center through a η7-hapticity. Vaporization of the graphite intercalation compounds graphite–Y or graphite– leads to the formation of endohedral fullerenes such as Y@C82. Electron spin resonance studies indicated the formation of Y3+ and (C82)3− ion pairs. The carbides Y3C, Y2C, and YC2 can each hydrolyze to form hydrocarbons.
Yttrium isotopes are among the most common products of the nuclear fission of uranium occurring in nuclear explosions and nuclear reactors. In terms of waste management, the most important yttrium isotopes are 91Y and 90Y, with half-lives of 58.51 days and 64 hours, respectively. The first is formed directly from fission, while the latter, despite its short half-life, is in secular equilibrium with its long-lived parent isotope, strontium-90 (90Sr) with a half-life of 29 years.
All group 3 elements have an odd number of protons and therefore have few stable isotopes. Yttrium itself has only one stable isotope, 89Y, which is also its only naturally occurring one. 89Y is thought to be more abundant than it otherwise would be, due in part to the s-process which allows enough time for isotopes created by other processes to decay by electron emission (neutron → proton). Such a slow process tends to favor isotopes with mass numbers (A = protons + neutrons) around 90, 138 and 208, which have unusually stable atomic nuclei with 50, 82 and 126 neutrons, respectively. 89Y has a mass number close to 90 and has 50 neutrons in its nucleus.
At least 32 synthetic isotopes of yttrium have been observed, ranging in mass number from 76 to 108. The least stable of these is 106Y with a half-life of >150 ns (76Y has a half-life of >200 ns) and the most stable is 88Y with a half-life of 106.626 days. Besides the isotopes 91Y, 87Y, and 90Y, with half lives of 58.51 days, 79.8 hours, and 64 hours, respectively, all the other isotopes have half lives of less than a day and most of those have half-lives of less than an hour.
Yttrium isotopes with mass numbers at or below 88 decay primarily by positron emission (proton → neutron) to form strontium (Z = 38) isotopes. Yttrium isotopes with mass numbers at or above 90 decay primarily by electron emission (neutron → proton) to form zirconium (Z = 40) isotopes. Isotopes with mass numbers at or above 97 are also known to have minor decay paths of β− delayed neutron emission.
Yttrium has at least 20 metastable or excited isomers ranging in mass number from 78 to 102. Multiple excitation states have been observed for 80Y and 97Y. While most of yttrium's isomers are expected to be less stable than their ground state, 78mY, 84mY, 85mY, 96mY, 98m1Y, 100mY, and 102mY have longer half-lives than their ground states, as these isomers decay by beta decay rather than isomeric transition.
Johan Gadolin at the University of Åbo identified a new oxide or "earth" in Arrhenius' sample in 1789, and published his completed analysis in 1794. Anders Gustaf Ekeberg confirmed this in 1797 and named the new oxide yttria. In the decades after Antoine Lavoisier developed the first modern definition of chemical elements, it was believed that earths could be reduced to their elements, meaning that the discovery of a new earth was equivalent to the discovery of the element within, which in this case would have been yttrium.
Carl Gustav Mosander found in 1843 that samples of yttria actually contained three oxides: yttria (white yttrium oxide), erbia (yellow terbium oxide) and the rose-colored terbia (erbium oxide). A fourth oxide, ytterbium oxide, was isolated in 1878 by Jean Charles Galissard de Marignac. New elements would later be isolated from each of those oxides, and each element was named, in some fashion, after Ytterby, the village near the quarry in which they were found (see ytterbium, terbium, and erbium). In the following decades, seven other new metals were discovered in "Gadolin's yttria". Since yttria was a mineral after all and not an oxide, Martin Heinrich Klaproth renamed it gadolinite in honor of Gadolin.
In 1987, yttrium barium copper oxide was found to achieve high-temperature superconductivity. It was only the second material known to exhibit this property, and it was the first known material to achieve superconductivity above the (economically important) boiling point of nitrogen.
Yttrium is found in almost all rare earth minerals, as well as some uranium ores, but it is never found in nature as a free element. About 31 ppm of the Earth's crust is yttrium, making it the 28th most abundant element there, and 400 times more common than silver. Yttrium is found in soil in concentrations between 10 and 150 ppm (dry weight average of 23 ppm) and in sea water at 9 ppt. Lunar rock samples collected during the Apollo program have a relatively high yttrium content.
Yttrium has no known biological role, though it is found in most, if not all, organisms and tends to concentrate in the liver, kidney, spleen, lungs, and bones of humans. There is normally as little as 0.5 milligrams found within the entire human body; human breast milk contains 4 ppm. Yttrium can be found in edible plants in concentrations between 20 ppm and 100 ppm (fresh weight), with cabbage having the largest amount. With up to 700 ppm, the seeds of woody plants have the highest known concentrations.
There are four main sources for REEs:
It is difficult to separate yttrium from other rare earths. One method to obtain pure yttrium from the mixed oxide ores is to dissolve the oxide in sulfuric acid and fractionate it by ion exchange chromatography. With the addition of oxalic acid, the yttrium oxalate precipitates. The oxalate is converted into the oxide by heating under oxygen. By reacting the resulting yttrium oxide with hydrogen fluoride, yttrium fluoride is obtained.
Annual world production of yttrium oxide had reached 600 tonnes by 2001, with reserves estimated at 9 million tonnes. Only a few tonnes of yttrium metal are produced each year by reducing yttrium fluoride to a metal sponge with calcium magnesium alloy. The temperature of an arc furnace of above 1,600 °C is sufficient to melt the yttrium.
Yttria () is widely used to make YVO4:Eu and :Eu phosphors that give the red color in color television picture tubes, though the red color itself is actually emitted from the europium while the yttrium collects energy from the electron gun and passes it to the phosphor. Yttria is also used as a sintering additive in the production of porous silicon nitride and as a common starting material for both material science and for producing other compounds of yttrium.
Yttrium compounds are used as a catalyst for ethylene polymerization. As a metal, it is used on the electrodes of some high-performance spark plugs. Yttrium is also used in the manufacturing of gas mantles for propane lanterns as a replacement for thorium, which is radioactive.
Developing uses include yttrium-stabilized zirconia in particular as a solid electrolyte and as an oxygen sensor in automobile exhaust systems.
YAG, yttria, yttrium lithium fluoride and yttrium orthovanadate are used in combination with dopants such as neodymium, erbium, ytterbium in near-infrared lasers. YAG lasers have the ability to operate at high power and are used for drilling into and cutting metal. The single crystals of doped YAG are normally produced by the Czochralski process.
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). Yttrium oxide can also be used in ceramic and glass formulas, since it has a high melting point and imparts shock resistance and low thermal expansion characteristics. It is therefore used in camera lenses.
Needles made of yttrium-90, which can cut more precisely than scalpels, have been used to sever pain-transmitting nerves in the spinal cord, and yttrium-90 is also used to carry out radionuclide synovectomy in the treatment of inflamed joints, especially knees, in sufferers of conditions such as rheumatoid arthritis.
A neodymium-doped yttrium-aluminium-garnet laser has been used in an experimental, robot-assisted radical prostatectomy in canines in an attempt to reduce collateral nerve and tissue damage, whilst the erbium-doped ones are starting to be used in cosmetic skin resurfacing.
Yttrium was used in the yttrium barium copper oxide (YBa2Cu3O7, aka 'YBCO' or '1-2-3') superconductor developed at the University of Alabama and the University of Houston in 1987. This superconductor operated at 93 K, notable because this is above liquid nitrogen's boiling point (77.1 K). As the price of liquid nitrogen is lower than that of liquid helium, which has to be used for the metallic superconductors, the operating costs would decrease. The created material was a black and green, multi-crystal, multi-phase mineral. Researchers are studying a class of materials known as perovskites that are alternative mixtures of these elements, hoping to eventually develop a practical high-temperature superconductor.
Exposure to yttrium compounds in humans may cause lung disease. Workers exposed to airborne yttrium europium vanadate dust experienced mild eye, skin, and upper respiratory tract irritation—though this may have been caused by the vanadium content rather than the yttrium. Acute exposure to yttrium compounds can cause shortness of breath, coughing, chest pain, and cyanosis. NIOSH recommends a time-weighted average limit of 1 mg/m3 and an IDLH of 500 mg/m3. Yttrium dust is flammable.
Wipo Publishes Patent of Jx Nippon Mining & Metals for "High-Purity Yttrium, Process for Producing High-Purity Yttrium, High-Purity Yttrium Sputtering Target, Metal Gate Film Deposited with High-Purity Yttrium Sputtering Target and Semiconductor Element and Device Equipped with Said Metal Gate Film" (Japanese Inventor)
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The 2009 Import and Export Market for Calcium, Strontium, Barium, Rare Earth Metals, Scandium, and Yttrium in Iran.
Nov 21, 2009; Research and Markets (httpwww.researchandmarkets.com/research/11a112/the_2009_import_an) has announced the addition of the "The...
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