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The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), [1] are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals. Compounds containing rare ...
The term rare-earth element or rare-earth metal is often used to include the stable group 3 elements Sc, Y, and Lu in addition to the 4f elements. [8] All lanthanide elements form trivalent cations, Ln 3+, whose chemistry is largely determined by the ionic radius, which decreases steadily from lanthanum (La) to lutetium (Lu).
It is the sixth-most abundant rare-earth element and fourth-most abundant lanthanide, making up 9.1 parts per million of the Earth's crust, an abundance similar to that of boron. In 1841, Swedish chemist Carl Gustav Mosander extracted a rare-earth oxide residue he called didymium from a residue he called "lanthana", in turn separated from ...
A piece of yttrium. Yttrium is difficult to separate from other rare-earth elements. Rare-earth elements (REEs) come mainly from four sources: [58] Carbonate and fluoride containing ores such as the LREE bastnäsite ((Ce, La, etc.)(CO 3)F) contain on average 0.1% [15] [56] yttrium compared to the 99.9% for the 16 other REEs. [56]
An overview of one of the regolith-hosted rare earth element deposits (a type of Rare Earth Element mine) in South China [1]. Regolith-hosted rare earth element deposits (also known as ion-adsorption deposits) are rare-earth element (REE) ores in decomposed rocks that are formed by intense weathering of REE-rich parental rocks (e.g. granite, tuff etc.) in subtropical areas. [2]
Neodymium is a fairly common element in the Earth's crust for being a rare-earth metal. Most rare-earth metals are less abundant. Neodymium is classified as a lithophile under the Goldschmidt classification, meaning that it is generally found combined with oxygen. Although it belongs to the rare-earth metals, neodymium is not rare at all. Its ...
Several rare earth metals, including lutetium, are separated as a double salt with ammonium nitrate by crystallization. Lutetium is separated by ion exchange. In this process, rare-earth ions are adsorbed onto suitable ion-exchange resin by exchange with hydrogen, ammonium or cupric ions present in the resin. Lutetium salts are then selectively ...
Holmium(III) oxide, or holmium oxide is a chemical compound of the rare-earth element holmium and oxygen with the formula Ho 2 O 3.Together with dysprosium(III) oxide (Dy 2 O 3), holmium oxide is one of the most powerfully paramagnetic substances known.