GC: n
CT: Neodymium is considered a rare earth element because it is one of the 15 lanthanide elements that form the core of the rare earth element group. With atomic number 60, neodymium sits between praseodymium (59) and samarium (62) in the lanthanide series.
Neodymium is considered a critical raw material because it is the essential component in the world’s strongest permanent magnets, which are irreplaceable in numerous high-technology and clean energy applications.
S: Briandcolwell.com (last access: 27 January 2026)
N: 1. From the Greek νεο (neo), or new, and dymium took from didymium. Didymium, after the Greek δίδυμος (didymos), or twin.
- The name derives from the Greek neos for “new” and didymos for “twin”. It was discovered by the Swedish surgeon and chemist Carl Gustav Mosander in 1841, who called it didymium (or twin) because of its similarity to lanthanum, which he had previously discovered two years earlier. In 1885, the Austrian chemist Carl Auer (Baron von Welsbach) separated didymium into two elements, one of which he called neodymium (or new twin).
2. Neodymium is a soft, silvery-white metal. Its chemical symbol is Nd, and its atomic number is 60. This element is one of the lanthanides and is a rare earth metal. Although neodymium is classified as a rare earth, it is a fairly common element and is no rarer than nickel and copper. It tarnishes (rusts) easily when exposed to air, forming a flaky oxide coating that does not protect the metal from further oxidation (rusting). When it rusts, the element has a reddish-purple color. Neodymium compounds have numerous practical applications, playing a role in permanent magnets and lasers that are used in medicine.
3. Neodymium is a ductile and malleable silvery white metal. It oxidizes readily in air to form an oxide, Nd2O3, which easily spalls, exposing the metal to further oxidation. The metal must be stored sealed in a plastic covering or kept in vacuum or in an inert atmosphere. It reacts gradually with mineral acids—except hydrofluoric acid (HF), in which it forms a protective layer of trifluoride, NdF3. Neodymium is strongly paramagnetic and orders antiferromagnetically at 7.5 and 19.9 K (−265.7 and −253.3 °C, or −446.2 and −423.9 °F) with spontaneous magnetic moments developing separately on different independent sites, hexagonal and cubic, respectively.
Austrian chemist Carl Auer von Welsbach discovered neodymium in 1885 by separating ammonium didymium nitrate prepared from didymia (a mixture of rare-earth oxides) into a neodymium fraction and a praseodymium fraction by repeated crystallization. Of the rare earths, only yttrium, lanthanum, and cerium are more plentiful than neodymium. In the igneous rocks of Earth’s crust, it is more than twice as abundant as lead and about half as plentiful as copper.
4. Natural neodymium is a mixture of seven different isotopes. Five of them are stable—neodymium-142 (27.13 percent), neodymium-146 (17.19 percent), neodymium-143 (12.18 percent), neodymium-145 (8.30 percent), and neodymium-148 (5.76 percent)—and two are radioactive, neodymium-144 (23.80 percent) and neodymium-150 (5.64 percent). A total of 31 radioactive isotopes of neodymium (excluding nuclear isomers) have been characterized, ranging in mass from 124 to 161 and in half-life from 0.65 second (neodymium-125) to 7.9 × 1018 years (neodymium-150).
5. Chemistry; Geochemistry; Compartment – Canadian Nuclear Safety Commission: Nd (symbol), neodymium.
- A metallic element and member of the rare earth group, occurring in combination with cerium, lanthanum, and other rare earth metals.
- [Neodymium is] silvery-white to yellowish and … tarnishes quickly in air.
- neodymium: term adopted by Environment Canada; used in the list of pollutants measured in the National Air Pollution Surveillance Network (NAPS).
S: 1. Wordorigins.org (last access: 28 January 2026); CIAAW (last access: 28 January 2026). 2. EBSCO (last access: 27 January 2026). 3 & 4. EncBrit (last access: 28 January 2026). 5. TERMIUM PLUS (last access: 28 January 2026).
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CR: air-gap generator, copper, hybrid car, magnetic energy, rare earth elements, wind turbine (1), wind turbine (2).
