Yttrium

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Yttrium [ ʏtriʊm ] is a chemical element with the element symbol Y and atomic number 39 It belongs to the transition metals and the rare earth metals in the periodic table it is in the fifth period and the third sub-group (group 3) or scandium. Yttrium is after the first locality, the pit Ytterby in Stockholm, named, as well as ytterbium, terbium and erbium.

History

Yttrium was discovered in 1794 by Johan Gadolin in mineral Ytterbit. 1824 Friedrich Wöhler asked contaminated yttrium by reduction of yttrium chloride with potassium ago. It was not until 1842, Carl Gustav Mosander the separation of yttrium from the accompanying elements erbium and terbium.

Occurrence

Yttrium is not found in nature in the elemental state. Yttrium-containing minerals ( ytterbium earths ) are always found together with other rare earth metals. Also in uranium ores may be included. Commercially exploitable are Monazitsande, containing up to 3% yttrium, and Bastnäsit containing 0.2 % yttrium. Furthermore, it is the main component of the xenotime (Y [ PO4 ] ).

Large Monazitvorkommen that were discovered and exploited in the early 19th century in Brazil and India, the two countries made the main producers of Yttriumerzen. It was not until the opening of the Mountain Pass mine in California, which promoted large amounts of Bastnäsit up in the 1990s, made the U.S. the main producers of yttrium, although there degraded Bastnäsit contains little yttrium. Since the closure of this mine is China with 60% of the largest producer of rare earths. These are obtained in a mine near Bayan Kuang, whose ore contains xenotime, and from ion absorbing clay minerals, which are mined mainly in the south of China,.

Production and representation

The separation of rare earth elements from each other is an expensive step in the production of yttrium. Fractional crystallization of salt solutions is the preferred method at the beginning, this was used at an early stage for the separation of rare earth elements on a laboratory scale. Before the introduction of the ion chromatography has made it possible to separate the rare earths on an industrial scale.

The concentrated yttrium oxide is converted to fluoride. The subsequent reduction of the metal occurs with calcium in a vacuum induction furnace.

Properties

Yttrium is relatively stable in air, but darkens light. Some fresh interfaces can ignite at temperatures above 400 ° C. Finely divided yttrium is relatively unstable. Yttrium has a low cross section for neutron.

In its compounds it is usually trivalent. However, there are also cluster compounds in which yttrium oxidation <3 can assume. Yttrium is one of the light metals.

Isotopes

There are a total of 32 known isotopes between 76Y and 108Y, and another 24 Kernisomere. Of these, only a 89Y, also from the natural yttrium exists solely stable. It thus concerns with yttrium to one of 22 pure elements. The most stable radioisotopes are 88Y with a half -life of 106.65 days and 91Y with a half -life of 58.51 days. All other isotopes have a half-life less than one day, except for 87Y, which has a half-life of 79.8 hours and 90Y with 64 hours. Yttrium isotopes are among the most common products of the fission of uranium in nuclear reactors and nuclear explosions.

→ List of yttrium isotopes

Use

Metallic yttrium is used in reactor technology for pipes. Cobalt alloy can be used as rare earth YCo5. Yttrium is used as a material for the heat in ion sources of mass spectrometers use. In metallurgy low Yttriumzusätze be used for grain refining, for example in iron - chromium-aluminum heating element alloys, chromium, molybdenum, titanium and zirconium. In aluminum and magnesium alloys, strength-increasing effect. Doping of lithium iron phosphate battery with yttrium increases performance and durability

Technically, the major oxide yttrium compounds:

• Yttrium nitrate as coating material in a mantle
• Yttrium aluminum garnet (YAG) laser is used as crystal
• Yttrium iron garnet ( YIG) microwave filters as
• Yttrium - stabilized zirconia as the solid electrolyte in fuel cells ( SOFC Solid Oxide Fuel Cell)

However, the most important use of yttrium and Yttriumoxidsulfide are the diverse applications in trivalent europium ( red) and thulium (blue) doped phosphors ( phosphors ) in television picture tubes, fluorescent tubes and radar.

Furthermore, yttrium ceramics and alloys used in:

• Lambda probes
• Superconductors (for example, yttrium barium copper oxide YBa2Cu3O7 -x)
• ODS alloys
• Spark

As a pure beta emitter 90Y used in nuclear medicine for the treatment, for example for synovectomy, radionuclide therapy of bone metastases and radioimmunotherapy.

Biology

Yttrium is considered non-essential and toxic ( TLV = 5 mg/m3).

Compounds

• Yttrium oxide Y2O3
• Yttrium aluminum garnet Y3Al5O12
• Yttrium - iron-garnet Y3Fe5O12
• Yttriumhydrid YH3 ( CAS: 13598-57-7, thermally stable hydride for nuclear engineering ) and YH2 ( CAS: 13598-35-1 )
• Yttrium fluoride YF3
• Yttrium YCl3
• Yttriumbromid YBr3 ( CAS: 13649-98-2 )
• Yttriumiodid YI3 ( CAS: 13470-38-7 )
• Yttriumsulfid Y2S3