Illustration of Neodymium

1885 Neodymium

The book of science

Tom Sharp

ViennaCarl Auer von Welsbach elements Illustration of Neodymium


From Mosander’s “didymium,” the twin of lanthanum— the green twin, praseodymium, and the new twin, neodymium, two new elements— Carl Auer von Welsbach, midwife.

Atomic number 60

Whose oxide in glass shows a lavender hue in daylight but pale blue in fluorescent light. Filters out yellow light. Mixed with other rare earths in mischmetal. Alloyed with iron and boron makes strong permanent magnets.


A vast unrealized potential for crediting neodymium with unworldly properties may someday rival kryptonite. When we have mapped the universe we can go back and map it again having found a new universe in the shadow of the old one.

Carl Gustaf Mosander had extracted the oxide of lanthanum from cerium, and called the pinkish residue as didymium, from the Greek word for “twins,” because of its similarity to lanthium. Paul-Émile Lecoq de Boisbaudran had already separated samarium from this residue, and Jean Charles Galissard de Marignac had separated gadolinium from it. Later, Eugène-Anatole Demarçay separated europium from Lecoq’s samarium.

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