Rare-earth element | Britannica.com
Rare-earth element, any member of the group of chemical elements consisting of three elements in Group 3 (scandium [Sc], yttrium [Y], and lanthanum [La]) and the first extended row of elements below the main body of the periodic table (cerium [Ce] through lutetium [Lu]). The elements cerium through lutetium are called the lanthanides, but …
