rare earth element (REE)
Rare earths, rare earth metals or rare earth elements ( REE ), are metals that are bound in and dissolved from rare minerals. Most rare earth metals belong to the chemical elements of the 3rd group of the periodic table and have atomic numbers 57 to 70.
There are 17 rare earth metals, some of which have special spectroscopic properties in pure form, which is shown in the emission behavior and absorption behavior and is used in components of optical transmission technology. For example, in optical fiber amplifiers, where the optical fibers are doped with the rare earths erbium (Er), ytterbium( Yb), thulium (Tm) or neodymium( Nd) and amplify radiating wavelengths, or in fiber lasers in which the core glass is doped with rare earth ions, or in DWDM technology for wavelength selection. Yttrium is also used in memory chips and plasma displays, lathan in rechargeable batteries, and neodymium in magnets and motors.
Rare earths are among the so-called Strategic Metals, which are used in technological innovations and therefore have strategic importance.
The following is a list of the 17 rare earth elements:
Scandium (ScJ), atomic number 21, Yttrium (Y), 39, Lanthanum (La), 57, Cerium (Ce), 58, Dysprosium (Dy), 66, Europium (Eu), 63, Erbium (Er), 68, Gadolinium (Gd), 64, Holmium (Ho), 67, Lutetium (Lu), 71, Neodymium (Nd), 60, Praseodymium (Pr), 59, Promethium (Pm), 61, Samarium (Sm), 62, Terbium (Tb), 65, Thulium (Tm), 69, Ytterbium (Yb), 70.