Background | Name | Sources | Uses | Substitutes and Alternative Sources
Background The rare earths are a relatively abundant group of elements consisting of scandium, yttrium, and the lanthanide series.
Scandium, atomic number 21, is the lightest rare earth element. Although its occurrence in crustal rocks is greater than lead, mercury, and the precious metals, scandium rarely occurs in concentrated quantities because it does not selectively combine with the common ore-forming anions.
Yttrium, atomic number 39, is chemically similar to the lanthanides and often occurs in the same minerals as a result of its similar ionic radius.
The lanthanides consist of a group of 15 elements with atomic numbers 57 through 71. They are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium.
The rare earths were discovered in 1787 by Swedish Army Lieutenant Karl Axel Arrhenius when he collected the black mineral ytterbite (later renamed gadolinite) from a feldspar and quartz mine near the village of Ytterby, Sweden.
