Erbium (Er), chemical element, a rare-earth metal of the lanthanide series of the periodic table. Pure erbium is a silvery white metal that is relatively stable in air. It slowly reacts with water and quickly dissolves in diluted acids, except hydrofluoric acid (HF) because of formation of the protective fluoride (ErF3) layer on the surface of the metal. Continue reading from Encyclopedia Britannica
In 1843, at Stockholm, Carl Mosander obtained two new metal oxides from yttrium, which had been know since 1794. One of these was erbium oxide, which was pink. (The other was terbium oxide, which was yellow.) While erbium was one of the first lanthanoid elements to be discovered, the picture is clouded because early samples of this element must have contained other rare-earths. We know this because In1878 Jean-Charles Galissard de Marignac, working at the University of Geneva, extracted another element from erbium and called it ytterbium. (This too was impure and scandium was extracted from it a year later.)
A sample of pure erbium metal was not produced until 1934, when Wilhelm Klemm and Heinrich Bommer achieved it by heating purified erbium chloride with potassium. Continue reading from Royal Society of Chemistry
Naturally occurring erbium is a mixture of six stable isotopes. In addition, nine radioactive isotopes of erbium are recognized. Erbium is finding uses in nuclear and metallurgical applications. When added to vanadium, erbium lowers the hardness and improves pliability of the metal. Erbium oxide adds a pink hue to glasses and porcelain enamel glazes. Named for the Swedish village Ytterby (as was ytterbium, terbium and yttrium). Continue reading from LiveScience