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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).
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 ...
First discovered 80 years ago in 1945, Promethium is a lanthanide (one of a series of 15 metallic chemicals also known as rare earth metals) with the atomic number 61, and in the following eight ...
Lanthanum is also ruefully considered a 'rare earth' metal because the process to mine it is difficult, time-consuming, and expensive. [17] Lanthanum is rarely the dominant lanthanide found in the rare earth minerals, and in their chemical formulae it is usually preceded by cerium.
Praseodymium always occurs naturally together with the other rare-earth metals. 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 ...
The lanthanides are the 15 rare-earth chemical elements which lie between lanthanum and lutetium on the periodic table. The lanthanides are trivalent metals.
It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard , slightly malleable , silvery metal that quickly tarnishes in air and moisture. When oxidized, neodymium reacts quickly producing pink, purple/blue and yellow compounds in the +2, +3 and +4 oxidation states .
Rare earth elements also only make up a tiny proportion of coal ash, Ziemkiewicz added, so their extraction “wouldn’t change the volume requiring disposal and storage.” Coal ash contains ...