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Rare-earth element
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Rare-earth elementsin the periodic table <table><tbody><tr><td><a href="/facts/Hydrogen/BoYHjl0J">Hydrogen</a></td><td colspan="30"></td><td><a href="/facts/Helium/yRul93TG">Helium</a></td></tr><tr><td><a href="/facts/Lithium/7vXX6BWA">Lithium</a></td><td><a href="/facts/Beryllium/dv295voP">Beryllium</a></td><td colspan="24"></td><td><a href="/facts/Boron/Pmwgd7Mf">Boron</a></td><td><a href="/facts/Carbon/ukrgQexo">Carbon</a></td><td><a href="/facts/Nitrogen/Nf1QpGDz">Nitrogen</a></td><td><a href="/facts/Oxygen/acyn6o8r">Oxygen</a></td><td><a href="/facts/Fluorine/YUV0Fb8m">Fluorine</a></td><td><a href="/facts/Neon/5bF1FwGL">Neon</a></td></tr><tr><td><a href="/facts/Sodium/eYuSPu2V">Sodium</a></td><td><a href="/facts/Magnesium/XyIhd2FG">Magnesium</a></td><td colspan="24"></td><td><a href="/facts/Aluminium/7wmR8jYE">Aluminium</a></td><td><a href="/facts/Silicon/cgWx0hdr">Silicon</a></td><td><a href="/facts/Phosphorus/27xCeIqs">Phosphorus</a></td><td><a href="/facts/Sulfur/IK0amTfM">Sulfur</a></td><td><a href="/facts/Chlorine/y27UwYBM">Chlorine</a></td><td><a href="/facts/Argon/QX6NRH6d">Argon</a></td></tr><tr><td><a href="/facts/Potassium/FWPwS7Rj">Potassium</a></td><td><a href="/facts/Calcium/hf252CC0">Calcium</a></td><td colspan="14"></td><td><a href="/facts/Scandium/TJRt1chg">Scandium</a></td><td><a href="/facts/Titanium/53ArnDoy">Titanium</a></td><td><a href="/facts/Vanadium/UvKkKTSm">Vanadium</a></td><td><a href="/facts/Chromium/6sVk6Uu7">Chromium</a></td><td><a href="/facts/Manganese/j9ELd1TL">Manganese</a></td><td><a href="/facts/Iron/QK1JYy8E">Iron</a></td><td><a href="/facts/Cobalt/gqhScEw4">Cobalt</a></td><td><a href="/facts/Nickel/KwMCHYRP">Nickel</a></td><td><a href="/facts/Copper/I8PEE8oX">Copper</a></td><td><a href="/facts/Zinc/80b1qgk3">Zinc</a></td><td><a href="/facts/Gallium/EucevDs9">Gallium</a></td><td><a href="/facts/Germanium/wtoALHGs">Germanium</a></td><td><a href="/facts/Arsenic/k1c4f44D">Arsenic</a></td><td><a href="/facts/Selenium/k975NApC">Selenium</a></td><td><a href="/facts/Bromine/oLfj3C7D">Bromine</a></td><td><a href="/facts/Krypton/llkNlCke">Krypton</a></td></tr><tr><td><a href="/facts/Rubidium/KDHSe2HM">Rubidium</a></td><td><a href="/facts/Strontium/ABaA5qQK">Strontium</a></td><td></td><td colspan="13"></td><td><a href="/facts/Yttrium/BlX6rj99">Yttrium</a></td><td><a href="/facts/Zirconium/y7gsoQFz">Zirconium</a></td><td><a href="/facts/Niobium/3zNI8AKp">Niobium</a></td><td><a href="/facts/Molybdenum/RX6vp2bF">Molybdenum</a></td><td><a href="/facts/Technetium/MGYWNI5d">Technetium</a></td><td><a href="/facts/Ruthenium/uzCm4ufn">Ruthenium</a></td><td><a href="/facts/Rhodium/xmBd9aFG">Rhodium</a></td><td><a href="/facts/Palladium/AXMwDFxs">Palladium</a></td><td><a href="/facts/Silver/xXe41BGg">Silver</a></td><td><a href="/facts/Cadmium/wXkV2eIX">Cadmium</a></td><td><a href="/facts/Indium/zRq3stVb">Indium</a></td><td><a href="/facts/Tin/obW9mqc3">Tin</a></td><td><a href="/facts/Antimony/YsA7lVgT">Antimony</a></td><td><a href="/facts/Tellurium/v7QvfIvS">Tellurium</a></td><td><a href="/facts/Iodine/JlfMecMf">Iodine</a></td><td><a href="/facts/Xenon/9E3XR69R">Xenon</a></td></tr><tr><td><a href="/facts/Caesium/dXKN1S5k">Caesium</a></td><td><a href="/facts/Barium/IkL09XHQ">Barium</a></td><td><a href="/facts/Lanthanum/Uhmmy1sB">Lanthanum</a></td><td><a href="/facts/Cerium/a7UjMBQ6">Cerium</a></td><td><a href="/facts/Praseodymium/2lnRJ9dH">Praseodymium</a></td><td><a href="/facts/Neodymium/GzDkTIoI">Neodymium</a></td><td><a href="/facts/Promethium/8xvCz9Rg">Promethium</a></td><td><a href="/facts/Samarium/09K3kl93">Samarium</a></td><td><a href="/facts/Europium/dqmBm1vr">Europium</a></td><td><a href="/facts/Gadolinium/eLYUeScu">Gadolinium</a></td><td><a href="/facts/Terbium/ICF3PMED">Terbium</a></td><td><a href="/facts/Dysprosium/eMev6zGS">Dysprosium</a></td><td><a href="/facts/Holmium/C73kJVtp">Holmium</a></td><td><a href="/facts/Erbium/XEJlgJcx">Erbium</a></td><td><a href="/facts/Thulium/G2905xhd">Thulium</a></td><td><a href="/facts/Ytterbium/3lerM9uf">Ytterbium</a></td><td><a href="/facts/Lutetium/URlmnYG8">Lutetium</a></td><td><a href="/facts/Hafnium/rBNnlxDS">Hafnium</a></td><td><a href="/facts/Tantalum/VwaxMm33">Tantalum</a></td><td><a href="/facts/Tungsten/WYwbNDYX">Tungsten</a></td><td><a href="/facts/Rhenium/TzyqJYEn">Rhenium</a></td><td><a href="/facts/Osmium/1TjXD69n">Osmium</a></td><td><a href="/facts/Iridium/TFQutoj1">Iridium</a></td><td><a href="/facts/Platinum/qJC6lQf7">Platinum</a></td><td><a href="/facts/Gold/1znknojp">Gold</a></td><td><a href="/facts/Mercury_(element)/WlxfoHva">Mercury (element)</a></td><td><a href="/facts/Thallium/v35pGMJB">Thallium</a></td><td><a href="/facts/Lead/EYljasJN">Lead</a></td><td><a href="/facts/Bismuth/75FLjkoX">Bismuth</a></td><td><a href="/facts/Polonium/G4rzsyjP">Polonium</a></td><td><a href="/facts/Astatine/AlbHPBK5">Astatine</a></td><td><a href="/facts/Radon/0V9arWKl">Radon</a></td></tr><tr><td><a href="/facts/Francium/P3Rz4gDP">Francium</a></td><td><a href="/facts/Radium/VWo5gkzn">Radium</a></td><td><a href="/facts/Actinium/GMQtJ4Gm">Actinium</a></td><td><a href="/facts/Thorium/ysdWH470">Thorium</a></td><td><a href="/facts/Protactinium/v87VqTPf">Protactinium</a></td><td><a href="/facts/Uranium/n2sGWBzU">Uranium</a></td><td><a href="/facts/Neptunium/pwp7Yvds">Neptunium</a></td><td><a href="/facts/Plutonium/4bUw9zH3">Plutonium</a></td><td><a href="/facts/Americium/rxL9Yc64">Americium</a></td><td><a href="/facts/Curium/LMyWXg8l">Curium</a></td><td><a href="/facts/Berkelium/ePryEYy3">Berkelium</a></td><td><a href="/facts/Californium/AJVjoVut">Californium</a></td><td><a href="/facts/Einsteinium/RePoIVN9">Einsteinium</a></td><td><a href="/facts/Fermium/Us3rnvG5">Fermium</a></td><td><a href="/facts/Mendelevium/bEHBu18F">Mendelevium</a></td><td><a href="/facts/Nobelium/syRkloSw">Nobelium</a></td><td><a href="/facts/Lawrencium/HVw2LVlx">Lawrencium</a></td><td><a href="/facts/Rutherfordium/44LSnv9p">Rutherfordium</a></td><td><a href="/facts/Dubnium/3CHC1lEt">Dubnium</a></td><td><a href="/facts/Seaborgium/ejs0Ap6P">Seaborgium</a></td><td><a href="/facts/Bohrium/epvp3GWM">Bohrium</a></td><td><a href="/facts/Hassium/t0bgGzwt">Hassium</a></td><td><a href="/facts/Meitnerium/pKaD3sRY">Meitnerium</a></td><td><a href="/facts/Darmstadtium/etmwTLmP">Darmstadtium</a></td><td><a href="/facts/Roentgenium/LEhvJaJQ">Roentgenium</a></td><td><a href="/facts/Copernicium/EhgyBkg0">Copernicium</a></td><td><a href="/facts/Nihonium/sb09p5dv">Nihonium</a></td><td><a href="/facts/Flerovium/Aa7uGMuG">Flerovium</a></td><td><a href="/facts/Moscovium/QhSEr0H5">Moscovium</a></td><td><a href="/facts/Livermorium/nQc1FE6E">Livermorium</a></td><td><a href="/facts/Tennessine/eGCBDvEr">Tennessine</a></td><td><a href="/facts/Oganesson/zs5MQDjV">Oganesson</a></td></tr></tbody></table> <p>The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the <a href="/facts/Lanthanide/rt3XIRCl">lanthanides</a> or lanthanoids (although <a href="/facts/Scandium/TJRt1chg">scandium</a> and <a href="/facts/Yttrium/BlX6rj99">yttrium</a>, which do not belong to this series, are usually included as rare earths), are a set of 17 nearly indistinguishable lustrous silvery-white soft <a href="/facts/Heavy_metals/Cblmy8qI">heavy metals</a>. Compounds containing rare earths have diverse applications in electrical and electronic components, lasers, glass, magnetic materials, and industrial processes. The term "rare-earth" is a <a href="/facts/Misnomer/P4TnsX3H">misnomer</a> because they are not actually scarce, but historically it took a long time to isolate these elements. They are relatively plentiful in the entire <a href="/facts/Earth%2527s_crust/VSy2u31r">Earth's crust</a> (<a href="/facts/Cerium/a7UjMBQ6">cerium</a> being the <a href="/facts/Abundance_of_elements_in_Earth%2527s_crust/UDSVHH56">25th-most-abundant element</a> at 68 parts per million, more abundant than <a href="/facts/Copper/I8PEE8oX">copper</a>), but in practice they are spread thinly as trace impurities, so to obtain rare earths at usable purity requires processing enormous amounts of raw ore at great expense; thus the name "rare" earths. </p><p>Scandium and yttrium are considered rare-earth elements because they tend to occur in the same <a href="/facts/Ore/kgc9DssX">ore</a> deposits as the lanthanides and exhibit similar chemical properties, but have different electrical and <a href="/facts/Magnetic_properties/eo75vApl">magnetic properties</a>. </p><p>These metals tarnish slowly in air at room temperature and react slowly with cold water to form hydroxides, liberating hydrogen. They react with steam to form oxides and ignite spontaneously at a temperature of 400 °C (752 °F). These elements and their compounds have no biological function other than in several specialized enzymes, such as in lanthanide-dependent methanol dehydrogenases in bacteria. The water-soluble compounds are mildly to moderately toxic, but the insoluble ones are not. All isotopes of <a href="/facts/Promethium/8xvCz9Rg">promethium</a> are radioactive, and it does not occur naturally in the earth's crust, except for a trace amount generated by <a href="/facts/Spontaneous_fission/0QuJoVKI">spontaneous fission</a> of <a href="/facts/Uranium-238/QhcHm6q8">uranium-238</a>. They are often found in <a href="/facts/Mineral/LkUFbNmv">minerals</a> with <a href="/facts/Thorium/ysdWH470">thorium</a>, and less commonly <a href="/facts/Uranium/n2sGWBzU">uranium</a>. </p><p>Because of their <a href="/facts/Geochemical/05094gDu">geochemical</a> properties, rare-earth elements are typically dispersed and not often found concentrated in <a href="/facts/Rare-earth_mineral/lwsQA1sh">rare-earth minerals</a>. Consequently, economically exploitable <a href="/facts/Ore/kgc9DssX">ore deposits</a> are sparse. The first rare-earth mineral discovered (1787) was <a href="/facts/Gadolinite/kahQI57c">gadolinite</a>, a black mineral composed of cerium, yttrium, iron, silicon, and other elements. This mineral was extracted from a mine in the village of <a href="/facts/Ytterby/6CaEoUjc">Ytterby</a> in <a href="/facts/Sweden/u3qC7lyj">Sweden</a>. Four of the rare-earth elements bear names derived from this single location. </p>