rare-earth metals definition of rare-earth metals in the Free Online Encyclopedia.

rare-earth metals, in chemistry, group of metals including those of the lanthanide series lanthanide series, a series of metallic elements, included in the rare-earth metals, in Group 3 of the periodic table. Members of the series are often called lanthanides, although lanthanum (atomic number 57) is not always considered a member of the series.
..... Click the link for more information. and actinide series actinide series, a series of radioactive metallic elements in Group 3 of the periodic table. Members of the series are often called actinides, although actinium (at. no. 89) is not always considered a member of the series.
..... Click the link for more information. , usually yttrium yttrium [for Ytterby, a town in Sweden], metallic chemical element; symbol Y; at. no. 39; at. wt. 88.9059; m.p. about 1,522°C;; b.p. 3,338°C;; sp. gr. about 4.45; valence +3. Yttrium is a highly crystalline iron-gray metal.
..... Click the link for more information. , sometimes scandium scandium , metallic chemical element; symbol Sc; at. no. 21; at. wt. 44.9559; m.p. 1,541°C;; b.p. 2,831°C;; sp. gr. 2.99 at 20°C;; valence +3. Scandium is a soft silver-white metal.
..... Click the link for more information. and thorium thorium [from Thor], radioactive chemical element; symbol Th; at. no. 90; at. wt. 232.0381; m.p. about 1,750°C;; b.p. about 4,790°C;; sp. gr. 11.7 at 20°C;; valence +4.

Thorium is a soft, ductile, lustrous, silver-white, radioactive metal.
..... Click the link for more information. , and rarely zirconium zirconium , metallic chemical element; symbol Zr; at. no. 40; at. wt. 91.22; m.p. about 1,852°C;; b.p. 4,377°C;; sp. gr. 6.5 at 20°C;; valence +2, +3, or +4.

Zirconium is a very strong, malleable, ductile, lustrous silver-gray metal.
..... Click the link for more information. . Promethium, which is not found in nature, is not usually considered a rare-earth metal. The metals usually occur together in minerals as their oxides (rare earths rare earths, in chemistry, oxides of the rare-earth metals. They were once thought to be elements themselves. They are widely distributed in the earth's crust and are fairly abundant, although they were once thought to be very scarce.
..... Click the link for more information. ) and are somewhat difficult to separate because of their chemical similarity. A subgroup of the rare-earth metals, consisting of those with atomic numbers between 57 and 63 and ytterbium, is often called the cerium metals. Misch metal is an alloy of the cerium metals often used in lighter flints, in alloys with other metals (especially magnesium magnesium , metallic chemical element; symbol Mg; at. no. 12; at. wt. 24.305; m.p. about 648.8°C;; b.p. about 1,090°C;; sp. gr. 1.738 at 20°C;; valence +2.
..... Click the link for more information. ), and to remove residual gases in the manufacture of vacuum tubes. Individual metals may be isolated as their compounds by ion exchange methods, solvent extraction, or fractional crystallization, and chemically or electrolytically reduced to the pure metal. Uses are discussed in articles on individual elements.

Bibliography

See F. H. Spedding and A. H. Daane, ed., The Rare Earths (1961, repr. 1971); E. C. Subbarao and W. E. Wallace, ed., Science and Technology of Rare Earth Metals (1980).

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No references found	But titanium dioxide on its own doesn't perform well enough to replace the expensive, rare-earth metals or fire-prone carbon-based materials used in today's lithium-ion batteries. A splash of graphene can improve battery materials by Asian News International The two sides agreed that there are good prospects of cooperation in energy sector, rare-earth metals, agricultural and processing sector, tourism industry. Kyrgyz Ambassador to Germany visits Denmark on working visit by AKIpress News Agency The government in Nouakchott is now attempting to revive the mining sector as a spur to economic growth and is trying to interest foreign companies not only in iron ore, copper and gypsum but also in gold, chrome, lead, lithium, molybdenum, rare-earth metals, tin, uranium, tungsten and zinc - all of which are found in Mauritania. Welcome mat is out for mining investors by Bromby, Robin / African Business	Rappahannock River Valley National Wildlife Refuge Rapperswil RAPPORT RAPT Raptanov, Timofei Raptanov, Timofei Alekseevich Rapti raptor raptorial rapture of the deep Rapunzel Rara rare rare earth rare earth metal rare earths rare gas Rare Metal rare mode rare set rare-earth alloy rare-earth chelate laser Rare-Earth Element rare-earth garnet rare-earth magnet rare-earth metals rare-earth mineral rare-earth salts rare-earth-doped fiber amplifier Rare-Metals Industry, Institute of the rarefaction rarefaction wave rarefied rarefied gas Rarefied gas flow rarefraction RAREP Rarita-Schwinger equation Raritan Rarotonga RARP Rarytkin RAS Ras Addar Ras al-Khaimah Ras al-Tannurah Ras at Tib Ras Dashen Ras protein Ras Shamra Rasa	Rare Record Price Guide RARE SALAMI rare set Rare Species Conservatory Foundation Rare Symmetry Violating Processes Rare Threatened or Endangered Rare Ware Rare Witch Project Rare, Endangered and Threatened Rare-book Rare-Book Digital Library rare-earth alloy rare-earth barium-copper-oxide rare-earth chelate laser Rare-Earth Cobalt rare-earth element rare-earth element rare-earth element rare-earth garnet rare-earth intensifying screen rare-earth intensifying screen Rare-Earth Iron Garnet Rare-Earth Laser Device Rare-earth magnet Rare-Earth Metal Rare-Earth Metal Hydride rare-earth metals Rare-earth mineral Rare-earth minerals rare-earth salts rare-earth screen rare-earth screen rare-earth screen rare-earth screen rare-earth screen rare-earth-doped fiber amplifier Rare-Metals Industry, Institute of the rare-roasted rarebit rarebits Rarebyte RAREC Raredos Raredos raree show raree-show raree-shows RAREF rarefaction rarefaction rarefaction rarefaction wave rarefaction, bone Rarefaction-Condensation Differential Potential rarefactions rarefactions rarefactions

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But titanium dioxide on its own doesn't perform well enough to replace the expensive, rare-earth metals or fire-prone carbon-based materials used in today's lithium-ion batteries.

A splash of graphene can improve battery materials by Asian News International

The two sides agreed that there are good prospects of cooperation in energy sector, rare-earth metals, agricultural and processing sector, tourism industry.

Kyrgyz Ambassador to Germany visits Denmark on working visit by AKIpress News Agency

The government in Nouakchott is now attempting to revive the mining sector as a spur to economic growth and is trying to interest foreign companies not only in iron ore, copper and gypsum but also in gold, chrome, lead, lithium, molybdenum, rare-earth metals, tin, uranium, tungsten and zinc - all of which are found in Mauritania.

Welcome mat is out for mining investors by Bromby, Robin / African Business

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