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Jai Ganesh

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Ytterbium

Ytterbium

Gist

Ytterbium (Yb) is a soft, silver-colored chemical element (atomic number 70) belonging to the rare earth metals, named after the Swedish town of Ytterby where it was discovered. It's used in electronics as a dopant for phosphors and in ceramic capacitors, as a pressure sensor, and in lasers. Ytterbium is known for its low density and melting/boiling points compared to other lanthanides and forms stable compounds in its +3 oxidation state, though it also has a +2 state.

Ytterbium is beginning to find a variety of uses, such as in memory devices and tuneable lasers. It can also be used as an industrial catalyst and is increasingly being used to replace other catalysts considered to be too toxic and polluting.

Summary

Ytterbium is a chemical element; it has symbol Yb and atomic number 70. It is a metal, the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. Like the other lanthanides, its most common oxidation state is +3, as in its oxide, halides, and other compounds. In aqueous solution, like compounds of other late lanthanides, soluble ytterbium compounds form complexes with nine water molecules. Because of its closed-shell electron configuration, its density, melting point and boiling point are much lower than those of most other lanthanides.

In 1878, Swiss chemist Jean Charles Galissard de Marignac separated from the rare earth "erbia", another independent component, which he called "ytterbia", for Ytterby, the village in Sweden near where he found the new component of erbium. He suspected that ytterbia was a compound of a new element that he called "ytterbium". Four elements were named after the village, the others being yttrium, terbium, and erbium. In 1907, the new earth "lutecia" was separated from ytterbia, from which the element "lutecium", now lutetium, was extracted by Georges Urbain, Carl Auer von Welsbach, and Charles James. After some discussion, Marignac's name "ytterbium" was retained. A relatively pure sample of the metal was first obtained in 1953. At present, ytterbium is mainly used as a dopant of stainless steel or active laser media, and less often as a gamma ray source.

Natural ytterbium is a mixture of seven stable isotopes, which altogether are present at an average concentration of 0.3 parts per million in the Earth's crust. This element is mined in China, the United States, Brazil, and India in form of the minerals monazite, euxenite, and xenotime. The ytterbium concentration is low because it is found only among many other rare-earth elements. It is among the least abundant. Once extracted and prepared, ytterbium is somewhat hazardous as an eye and skin irritant. The metal is a fire and explosion hazard.

Details

Ytterbium (Yb), chemical element, is a rare-earth metal of the lanthanide series of the periodic table.

Ytterbium is the most volatile rare-earth metal. It is a soft, malleable silvery metal that will tarnish slightly when stored in air and therefore should be stored in vacuum or in an inert atmosphere when long storage time is required. It slowly oxidizes in air, forming Yb2O3; the metal is readily dissolved in diluted acids—except hydrofluoric acid (HF), in which a protective layer of YbF3 forms on the surface and impedes further chemical reaction. Ytterbium is weakly paramagnetic, having the lowest magnetic susceptibility of all the rare-earth metals.

The first concentrate of ytterbium was obtained in 1878 by Swiss chemist Jean-Charles Galissard de Marignac and named by him for the town of Ytterby, Sweden, where it (and the first discovered rare-earth element, yttrium) was found. French chemist Georges Urbain and Austrian chemist Carl Auer von Welsbach independently demonstrated in 1907–08 that Marignac’s earth was composed of two oxides, which Urbain called neoytterbia and lutetia. The elements are now known as ytterbium and lutetium. Ytterbium is among the less-abundant rare earths. It occurs in minute amounts in many rare-earth minerals such as laterite clays, xenotime, and euxenite and is found in products of nuclear fission as well.

Natural ytterbium consists of seven stable isotopes: ytterbium-174 (32.0 percent), ytterbium-172 (21.7 percent), ytterbium-173 (16.1 percent), ytterbium-171 (14.1 percent), ytterbium-176 (13 percent), ytterbium-170 (3 percent), and ytterbium-168 (0.1 percent). Not counting nuclear isomers, a total of 27 radioactive isotopes of Yb ranging in mass from 148 to 181 with half-lives ranging from 409 milliseconds (ytterbium-154) to 32.018 days (ytterbium-169) have been characterized.

Ytterbium is separated from the other rare-earth elements by solvent-solvent extraction or ion-exchange techniques. The elemental metal is prepared by the metallothermic reduction of its oxide, Yb2O3, with lanthanum metal, followed by a vacuum distillation to further purify the metal. Ytterbium exists in three allotropic (structural) forms. The α-phase, which exists below 7 °C (45 °F), is close-packed hexagonal with a = 3.8799 Å and c = 6.3859 Å at room temperature. The β-phase is face-centred cubic with a = 5.4848 Å, and it is the normal structure at room temperature. The γ-phase is body-centred cubic with a = 4.44 Å at 763 °C (1,405 °F). Ytterbium has the lowest boiling point of the rare-earth metals.

The element has little practical use beyond research. Radioactive 169Yb isotope is a source of hard X-rays useful in portable radiographic devices. It is used as a dopant in a variety of optical materials, including lenses. The metal is used in pressure sensors because its electrical resistivity is strongly pressure-dependent.

Ytterbium, like europium, is a divalent metal. A compound of ytterbium in the +2 oxidation state was first prepared in 1929 by W.K. Klemm and W. Schuth, who reduced ytterbium trichloride, YbCl3, to ytterbium dichloride, YbCl2, with hydrogen. The ion Yb2+ has also been produced by electrolytic reduction or treatment of a Yb3+ salt with sodium amalgam. The element forms a series of pale green Yb2+ salts such as ytterbium sulfate, dibromide, hydroxide, and carbonate. The pale green ytterbium ion Yb2+ is unstable in aqueous solution and reduces water readily, liberating hydrogen; it is less stable than the comparable europium ion, Eu2+, and more stable than the samarium ion Sm2+. In its predominant +3 oxidation state, ytterbium forms a series of white salts including the trisulfate and the trinitrate; the sesquioxide is also white.

Element Properties

atomic number  :  70
atomic weight  :  173.04
melting point  :  819 °C (1,506 °F)
boiling point  :  1,196 °C (2,185 °F)
specific gravity  :  6.966 (24 °C, or 75 °F)
oxidation states  :  +2, +3.

Additional Information:

Appearance

A soft, silvery metal. It slowly oxidises in air, forming a protective surface layer.

Uses

Ytterbium is beginning to find a variety of uses, such as in memory devices and tuneable lasers. It can also be used as an industrial catalyst and is increasingly being used to replace other catalysts considered to be too toxic and polluting.

Biological role

Ytterbium has no known biological role. It has low toxicity.

Natural abundance

In common with many lanthanide elements, ytterbium is found principally in the mineral monazite. It can be extracted by ion exchange and solvent extraction.

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