samarium

American  

[suh-mair-ee-uhm] / səˈmɛər i əm /

noun

Chemistry.

1. a rare-earth metallic element discovered in samarskite. Sm; 150.35; 62; 7.49.

---

samarium British  

/ səˈmɛərɪəm /

noun

1. a silvery metallic element of the lanthanide series occurring chiefly in monazite and bastnaesite and used in carbon-arc lighting, as a doping agent in laser crystals, and as a neutron-absorber. Symbol: Sm; atomic no: 62; atomic wt: 150.36; valency: 2 or 3; relative density: 7.520; melting pt: 1074°C; boiling pt: 1794°C

---

samarium Scientific  

/ sə-mâr′ē-əm /

1. A silvery-white metallic element of the lanthanide series that exists in several forms and has seven naturally occurring isotopes. It is used to make glass that absorbs infrared light and to absorb neutrons in the fuel rods of nuclear reactors. Atomic number 62; atomic weight 150.36; melting point 1,072°C; boiling point 1,791°C; specific gravity approximately 7.50; valence 2, 3.

2. See Periodic Table

---

Etymology

Origin of samarium

From New Latin, dating back to 1875–80; samarskite, -ium

Example Sentences

The region holds deposits of many of the very elements China has placed under export controls: yttrium, scandium, erbium, europium, ytterbium, samarium, and lutetium.

From Barron's • Oct. 24, 2025

Rare earths, like samarium and terbium, are critical to the production of technologies set to shape the world in the coming decades – including electric vehicles and highly advanced weapons systems.

From BBC • Apr. 25, 2025

The 17 elements are: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium.

From Reuters • Jul. 5, 2023

Suchitra Sebastian, for example, led work with Lonzarich a few years ago on samarium hexaboride, an insulator that exhibits metal-like behaviour when exposed to strong magnetic fields6.

From Nature • Sep. 26, 2017

In 1879, however, Lecoq de Boisbaudran showed that Mosander’s “didymium” contained samarium; while the residual “didymium,” after removal of samarium, was split by Auer v.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 4 "Diameter" to "Dinarchus" by Various