Rare-earth element

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Rare-earth elements
in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium

A rare-earth element (REE) or rare-earth metal (REM), as defined bi IUPAC, is ane o a set o seventeen chemical elements in the periodic cairt, specifically the fifteen lanthanides, as well as scandium an yttrium. Scandium an yttrium are considered rare-earth elements acause thay tend tae occur in the same ore deposits as the lanthanides an exhibit seemilar chemical properties. For the same set o mineralogical, chemical, physical (especially electron shell configuration), an relatit reasons, a broader definition o rare earth elements includin the actinides is encountered in some cases. Thorium is a significant component o monazite an ither important rare earth minerals, an uranium an decay products are foond in others.[1] Baith series o elements begin on the periodic table in group 3 unner yttrium an scandium.

Rare-earth elements are cerium (Ce), dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), holmium (Ho), lanthanum (La), lutetium (Lu), neodymium (Nd), praseodymium (Pr), promethium (Pm), samarium (Sm), scandium (Sc), terbium (Tb), thulium (Tm), ytterbium (Yb), an yttrium (Y).

Despite thair name, rare-earth elements are – wi the exception o the radioactive promethium – relatively plentiful in Yird's crust, wi cerium bein the 25t maist abundant element at 68 pairts per million, mair abundant than copper. Thay are nae especially rare, but thay tend tae occur thegither in naitur an are difficult tae separate frae ane anither. Houiver, acause o thair geochemical properties, rare-earth elements are teepically dispersed an nae eften foond concentrated as rare-earth minerals in economically exploitable ore deposits. The first sic mineral discovered wis gadolinite, a mineral componed o cerium, yttrium, iron, silicon, an ither elements. This mineral wis extracted frae a mine in the veelage o Ytterby in Swaden; fower o the rare-earth elements bear names derived frae this single location.

List[eedit | eedit soorce]

A table listing the 17 rare-earth elements, thair atomic nummer an seembol, the etymology o thair names, an thair main usages (see an aw Applications o lanthanides) is providit here. Some o the rare-earth elements are named efter the scientists who discovered or elucidated thair elemental properties, an some efter thair geographical discovery.

Z Seembol Name Etymology Selected applications Abundance (ppm in earth's crust)
21 Sc Scandium frae Latin Scandia (Scandinavia). Licht aluminium-scandium alloys for aerospace components, additive in metal-halide lamps an mercury-vapor lamps,[2] radioactive tracing agent in ile refineries 18-25
39 Y Yttrium efter the veelage o Ytterby, Swaden, whaur the first rare earth ore wis discovered. Yttrium aluminium garnet (YAG) laser, yttrium vanadate (YVO4) as host for europium in televeesion reid phosphor, YBCO heich-temperature superconductors, yttria-stabilized zirconia (YSZ), yttrium iron garnet (YIG) microwave filters, energy-efficient licht bulbs, spark plugs, gas mantles, additive tae steel, cancer treatments 31
57 La Lanthanum frae the Greek "lanthanein", meanin to be hidden. High refractive index an alkali-resistant gless, flint, hydrogen storage, battery-electrodes, camera lenses, fluid catalytic cracking catalyst for ile refineries 39
58 Ce Cerium efter the dwarf planet Ceres, named efter the Roman goddess o agriculture. Chemical oxidizing agent, polishing powder, yellow colors in gless an ceramics, catalyst for self-cleaning ovens, fluid catalytic cracking catalyst for ile refineries, ferrocerium flints for lighters 66.5
59 Pr Praseodymium frae the Greek "prasios", meanin leek-green, an "didymos", meanin twin. Rare-earth magnets, lasers, core material for carbon arc lichtin, colorant in glasses an enamels, additive in didymium gless uised in welding goggles, ferrocerium firesteel (flint) products. 9.1
60 Nd Neodymium frae the Greek "neos", meanin new, an "didymos", meanin twin. Rare-earth magnets, lasers, violet colors in gless an ceramics, didymium gless, ceramic capacitors, electric motors o electric automobiles 41.5
61 Pm Promethium efter the Titan Prometheus, who brought fire tae mortals. Nuclear batteries, luminous paint 1.0 x 10−15
62 Sm Samarium efter mine offeecial, Vasili Samarsky-Bykhovets. Rare-earth magnets, lasers, neutron captur, masers, control rods o nuclear reactors 8
63 Eu Europium efter the continent o Europe. Red an blue phosphors, lasers, mercury-vapor lamps, fluorescent lamps, NMR relaxation agent .05
64 Gd Gadolinium efter Johan Gadolin (1760–1852), tae honour his investigation o rare earths. High refractive index gless or garnets, lasers, X-ray tubes, computer memories, neutron captur, MRI contrast agent, NMR relaxation agent, magnetostrictive alloys sic as Galfenol, steel additive 6.2
65 Tb Terbium efter the veelage o Ytterby, Swaden. Additive in Neodymium based magnets, green phosphors, lasers, fluorescent lamps, magnetostrictive alloys sic as terfenol-D, naval sonar seestems, stabilizer o fuel cells 1.2
66 Dy Dysprosium frae the Greek "dysprositos", meanin hard to get. Additive in Neodymium based magnets, lasers, magnetostrictive alloys sic as terfenol-D, haurd disk drives 5.2
67 Ho Holmium efter Stockholm (in Latin, "Holmia"), native ceety o ane o its discoverers. Lasers, wavelength calibration standards for optical spectrophotometers, magnets 1.4
68 Er Erbium efter the veelage o Ytterby, Swaden. Infrared lasers, vanadium steel, fiber-optic technology 2.8
69 Tm Thulium efter the mythological northren land o Thule. Portable X-ray machines, metal-halide lamps, lasers 0.5
70 Yb Ytterbium efter the veelage o Ytterby, Swaden. Infrared lasers, chemical reducing agent, decoy flares, stainless steel, stress gauges, nuclear medicine, monitoring earthquakes 3.0
71 Lu Lutetium efter Lutetia, the ceety that later became Paris. Positron emission tomography – PET scan detectors, heich-refractive-index gless, lutetium tantalate hosts for phosphors, catalyst uised in refineries, LED licht bulb 0.5

Abbreviations[eedit | eedit soorce]

The follaein abbreviations are eften uised:

  • RE = rare earth
  • REM = rare-earth metals
  • REE = rare-earth elements
  • REO = rare-earth oxides
  • REY = rare-earth elements an yttrium
  • LREE = licht rare-earth elements
  • HREE = hivy rare-earth elements

References[eedit | eedit soorce]

  1. The Elements, T Gray, 2007 Black Dog & Leventhal pp 118-122 Lanthanum and Cerium
  2. C. R. Hammond, "Section 4; The Elements", in CRC Handbook of Chemistry and Physics, 89th Edition (Internet Version 2009), David R. Lide, ed., CRC Press/Taylor and Francis, Boca Raton, FL.