Rare Earth Element

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. As defined by IUPAC, rare earth elements or rare earth metals are a collection of seventeen chemical elements in the periodic table, namely scandium, yttrium, and the fifteen lanthanoids. Scandium and yttrium are considered rare earths since they tend to occur in the same ore deposits as the lanthanoids and exhibit similar chemical properties. The term "rare earth" arises from the minerals from which they were first isolated, which were uncommon oxide-type minerals (earths) found in Gadolinite extracted from one mine in the village of Ytterby, Sweden. However, with the exception of the highly-unstable promethium, rare earth elements are found in relatively high concentrations in the earth's crust, with cerium being the 25th most abundant element in the earth's crust at 68 parts per million.