Gray-white metal m.p. 1529 ºC; 2784 ºF b.p. 2863 ºC; 5185 ºF density 9.066 g/cc (25 ºC); 565.972 pound/cubic foot (77 ºF)	memory peg
	1842 Carl Gustav Mosander, Sweden
	Ytterby, village in Sweden (just as Terbium, Yttrium, and Ytterbium!)

The story of discovery and naming of the rare earth element Erbium began with Carl Gustav Mosander splitting old yttria into three new elements, yttria proper, erbia, and terbia. These three names are without much fantasy derived from Ytterby, where the original yttria was found (cf. Yttrium). In 1860 the Swedish chemist Nils Johan Berlin (1812-1891) denied the existence of Mosander’s yellow-oxyde erbia, and gave this name to his rose-colored oxyde terbia. Delafontaine (1864, 1878) followed him in naming the earth with rose-colored oxyd erbia, but proved also that the yellow-oxyd earth existed, and gave this now the name terbia, thus:

color of oxyde	Mosander 1842	Delafontaine 1864, 1878	element
colorless	yttria	yttria	Yttrium
yellow	erbia	terbia	Terbium
rose	terbia	erbia	Erbium

In the 1870s the analysis of samarskite introduced a new phase in the discovery of the rare earth elements (cf. Samarium). In 1878, Jean Charles Galissard de Marignac, professor of Chemistry at the University of Geneva, separated erbia into two new earths, erbia and ytterbia (note). Marignac's erbia was the following year split by Cleve into erbia proper and two new earths, which he named Thulium and Holmium (note).

Erbia proper is Erbium oxyde, the element was alternatively named Neo-erbium (in Gmelin's Handbuch).

Information and illustrations of Ytterby's quarry and a location map is on the Ytterbium page. (Cf. also Terbium and Yttrium).

John and Gordon Marks suggested in 1994 the name Mendelevium (Me), after the Russian chemist Дмитрий Иванович Менделеев (Dmitrij Ivanovič Mendeleyev) (1834-1907). (Element 101 they renamed into Bohemium). The Marks brothers found the old names ugly and confusing. They offered alternative names that are equivalent contemporary (at the time and place of discovery) metaphors, both more euphonious and more memorable (note).

See also: Chronological list of discovery of the rare earths, their names in different languages etc. on the Yttrium page

• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 667-699.
• Seltene Erden. Gmelins Handbuch der anorganische Chemie, 8. Aufl.; System-Nummer 39 (1938).