Ten Rare Earths and the Stories Behind Their Names

Yttrium is the first stop because everything starts at Ytterby, the quarry on an island near Stockholm. Johan Gadolin identified a new earth in a black mineral from there in 1794, and the quarry went on to lend its name to four elements in all.

Carl Gustaf Mosander separated terbium in 1843 and named it for Ytterby as well. For a time in the nineteenth century the names terbium and erbium were accidentally swapped, so early literature has to be read with care.

Mosander separated erbium in the same 1843 campaign, and it shares the lasting confusion of names with terbium. Its modern importance is erbium-doped fibre amplifiers, which made long-haul fibre-optic communication economic.

Jean Charles Galissard de Marignac separated ytterbium in 1878, the fourth element named for Ytterby. It was later split again when Georges Urbain and Carl Auer von Welsbach each found lutetium inside it in 1907.

Holmium takes its name from Holmia, the Latin name for Stockholm, moving from the quarry to the capital. Delafontaine and Soret detected it spectroscopically in 1878, and Per Teodor Cleve isolated it at Uppsala in 1879.

Lars Fredrik Nilson found scandium in 1879 in the Scandinavian minerals euxenite and gadolinite, and the name looks north to Scandinavia. Per Teodor Cleve recognised it as the element Mendeleev had predicted in 1871 as eka-boron.

Cleve separated thulium at Uppsala in 1879 and named it for Thule, the far northern land of classical geography. It is the least abundant of the stable rare earths, which kept it a laboratory curiosity for most of a century.

Gadolinium, separated by Marignac in 1880, is named directly for Johan Gadolin, one of the very few naturally occurring elements named for a person. The name brings the trail back to the chemist who opened it at Ytterby.

Lecoq de Boisbaudran named dysprosium in 1886 from the Greek dysprositos, hard to get at, after more than thirty attempts at separation. This is the one name on the trail that records effort rather than a place or a person.

Lutetium was isolated in 1907 by Georges Urbain in Paris and Carl Auer von Welsbach in Vienna, independently and almost at once. The name comes from Lutetia, the Roman name for Paris, which was Urbain's proposal, and the priority dispute that followed was bitter.