Editing Samarium (section)

{{Use American English|date=December 2022}}
{{Infobox samarium}}
'''Samarium''' is a [[chemical element]]; it has [[chemical symbol|symbol]] '''Sm''' and [[atomic number]] 62. It is a moderately hard silvery [[metal]] that slowly oxidizes in air. Being a typical member of the [[lanthanide]] series, samarium usually has the [[oxidation state]] +3. Compounds of samarium(II) are also known, most notably the [[monoxide]] SmO, [[samarium monochalcogenides|monochalcogenides]] SmS, SmSe and SmTe, as well as [[samarium(II) iodide]].

Discovered in 1879 by French chemist [[Paul-Émile Lecoq de Boisbaudran]], samarium was named after the mineral [[samarskite]] from which it was isolated. The mineral itself was named after a Russian mine official, Colonel [[Vassili Samarsky-Bykhovets]], who thus became the first person to have a chemical element named after him, though the name was indirect.

Samarium occurs in concentration up to 2.8% in several minerals including [[cerite]], [[gadolinite]], samarskite, [[monazite]] and [[bastnäsite]], the last two being the most common commercial sources of the element. These minerals are mostly found in China, the United States, Brazil, India, Sri Lanka and Australia; China is by far the world leader in samarium mining and production.

The main commercial use of samarium is in [[samarium–cobalt magnet]]s, which have permanent [[magnet]]ization second only to [[neodymium magnet]]s; however, samarium compounds can withstand significantly higher temperatures, above {{convert|700|C|F}}, without losing their permanent magnetic properties. The [[radioisotope]] samarium-153 is the active component of the drug [[samarium (153Sm) lexidronam|samarium (<sup>153</sup>Sm) lexidronam]] (Quadramet), which kills cancer cells in [[lung cancer]], [[prostate cancer]], [[breast cancer]] and [[osteosarcoma]]. Another isotope, [[samarium-149]], is a strong [[neutron]] absorber and so is added to [[control rod]]s of [[nuclear reactor]]s. It also forms as a decay product during the reactor operation and is one of the important factors considered in the reactor design and operation. Other uses of samarium include [[catalysis]] of [[chemical reaction]]s, [[samarium–neodymium dating|radioactive dating]] and [[X-ray laser]]s. Samarium(II) iodide, in particular, is a common [[reducing agent]] in [[chemical synthesis]].

Samarium has no biological role; some samarium salts are slightly toxic.<ref name=emsley />