Editing Samarium (section)

==Applications==
[[File:Samariumiodide.jpg|thumb|[[Barbier reaction]] using {{chem2|SmI2}}|alt=Barbier reaction using samarium diiodide]]

===Magnets===
An important use of samarium is [[samarium–cobalt magnet]]s, which are nominally {{chem2|SmCo5}} or {{chem2|Sm2Co17}}.<ref>{{cite web |url=https://www.stanfordmagnets.com/two-grades-of-samarium-cobalt-magnets-smco5-sm2co17.html |title=Two Grades of Samarium Cobalt Magnets: SmCo5 & Sm2Co17 |last=Marchio |first=Cathy |date=Apr 16, 2024 |website=Stanford Magnets |access-date=Aug 23, 2024}}</ref> They have high permanent magnetization, about 10,000 times that of iron and second only to [[neodymium magnet]]s. However, samarium magnets resist demagnetization better; they are stable to temperatures above {{convert|700|C|F}} (cf. 300–400&nbsp;°C for neodymium magnets). These magnets are found in small motors, headphones, and high-end magnetic [[Pick up (music technology)|pickup]]s for guitars and related musical instruments.<ref name="emsley" /> For example, they are used in the motors of a [[solar power|solar-powered]] [[electric aircraft]], the [[Solar Challenger]], and in the [[Vintage Noiseless|Samarium Cobalt Noiseless]] electric guitar and bass pickups.

===Chemical reagent===
Samarium and its compounds are important as catalysts and [[chemical reagent]]s. Samarium catalysts help the decomposition of plastics, dechlorination of pollutants such as [[polychlorinated biphenyl]]s (PCB), as well as dehydration and [[dehydrogenation]] of ethanol.<ref name="CRC" /> [[Lanthanide trifluoromethanesulfonates|Samarium(III) triflate]] {{chem2|Sm(OTf)3}}, that is {{chem2|Sm(CF3SO3)3}}, is one of the most efficient [[Lewis acid]] catalysts for a halogen-promoted [[Friedel–Crafts reaction]] with alkenes.<ref>{{cite journal|last1=Hajra |first1=S.|last2=Maji |first2=B.|last3=Bar |first3=S. |title=Samarium Triflate-Catalyzed Halogen-Promoted Friedel-Crafts Alkylation with Alkenes|date=2007|journal= [[Org. Lett.]]|volume= 9|issue= 15|pages= 2783–2786|doi= 10.1021/ol070813t|pmid=17585769}}</ref> [[Samarium(II) iodide]] is a very common reducing and coupling agent in [[organic synthesis]], for example in [[desulfonylation reactions]]; [[annulation]]; [[Danishefsky Taxol total synthesis|Danishefsky]], [[Kuwajima Taxol total synthesis|Kuwajima]], [[Mukaiyama Taxol total synthesis|Mukaiyama]] and [[Holton Taxol total synthesis|Holton Taxol total syntheses]]; [[strychnine total synthesis]]; [[Barbier reaction]] and other [[reductions with samarium(II) iodide]].<ref>{{cite book| page=1128| url=https://books.google.com/books?id=U3MWRONWAmMC&pg=PA1128|title =Advanced inorganic chemistry |edition=6th |last1= Cotton|first1=F. Albert |last2=Wilkinson |first2=Geoffrey |last3=Murillo |first3=Carlos A. |last4=Bochmann |first4=Manfred |publisher= Wiley|location=New Delhi, India|date=2007|isbn =978-81-265-1338-3}}</ref>

In its usual oxidized form, samarium is added to ceramics and glasses where it increases absorption of infrared light. As a (minor) part of [[mischmetal]], samarium is found in the "[[flint]]" ignition devices of many [[lighter]]s and torches.<ref name="emsley" /><ref name="CRC" />

===Neutron absorber===
Samarium-149 has a high [[neutron capture cross section|cross section for neutron capture]] (41,000&nbsp;[[barn (unit)|barns]]) and so is used in control rods of [[nuclear reactor]]s. Its advantage compared to competing materials, such as boron and cadmium, is stability of absorption – most of the fusion products of {{sup|149}}Sm are other isotopes of samarium that are also good [[neutron absorber]]s. For example, the cross section of samarium-151 is 15,000&nbsp;barns, it is on the order of hundreds of barns for {{sup|150}}Sm, {{sup|152}}Sm, and {{sup|153}}Sm, and 6,800&nbsp;barns for natural (mixed-isotope) samarium.<ref name="CRC" /><ref name="LA2" /><ref>[https://web.archive.org/web/20110706160607/http://www-nds.ipen.br/sgnucdat/b3.pdf Thermal neutron capture cross sections and resonance integrals – Fission product nuclear data]. ipen.br</ref>

===Lasers===
Samarium-doped [[calcium fluoride]] crystals were used as an active medium in one of the first [[solid-state laser]]s designed and built by [[Peter Sorokin]] (co-inventor of the [[dye laser]]) and Mirek Stevenson at [[IBM]] research labs in early 1961. This samarium laser gave pulses of red light at 708.5&nbsp;nm. It had to be cooled by liquid helium and so did not find practical applications.<ref>Bud, Robert and Gummett, Philip [https://books.google.com/books?id=HMx_6FtHBcUC&pg=PA268 ''Cold War, Hot Science: Applied Research in Britain's Defence Laboratories, 1945–1990''], NMSI Trading Ltd, 2002 {{ISBN|1-900747-47-2}} p. 268</ref><ref>{{cite journal|last1=Sorokin|first1=P. P.|title=Contributions of IBM to Laser Science—1960 to the Present|journal=IBM Journal of Research and Development|volume=23|page=476|date=1979|doi=10.1147/rd.235.0476|issue=5|bibcode=1979IBMJ...23..476S}}</ref> Another samarium-based laser became the first saturated [[X-ray laser]] operating at wavelengths shorter than 10 nanometers. It gave 50-picosecond pulses at 7.3 and 6.8&nbsp;nm suitable for uses in [[holography]], high-resolution [[microscopy]] of biological specimens, [[deflectometry]], [[interferometry]], and [[radiography]] of dense plasmas related to confinement fusion and [[astrophysics]]. Saturated operation meant that the maximum possible power was extracted from the lasing medium, resulting in the high peak energy of 0.3&nbsp;mJ. The active medium was samarium plasma produced by irradiating samarium-coated glass with a pulsed infrared [[Nd:YAG laser|Nd-glass laser]] (wavelength ~1.05&nbsp;μm).<ref>{{cite journal |last=Zhang |first=J. |title=A Saturated X-ray Laser Beam at 7 Nanometers |journal=Science |volume=276 |page=1097 |date=1997 |doi=10.1126/science.276.5315.1097 |issue=5315}}</ref>

===Storage phosphor===
In 2007 it was shown that nanocrystalline BaFCl:Sm{{sup|3+}} as prepared by co-precipitation can serve as a very efficient X-ray [[Photostimulated luminescence|storage phosphor]].<ref>{{cite journal|last1=Riesen|first1=Hans |last2=Kaczmarek|first2=Wieslaw |title=Efficient X-ray Generation of Sm{{sup|2+}} in Nanocrystalline BaFCl/Sm{{sup|3+}}: a Photoluminescent X-ray Storage Phosphor|journal=Inorganic Chemistry|date=2007-08-02|volume=46|issue=18|pages=7235–7 |doi=10.1021/ic062455g|pmid=17672448}}</ref> The co-precipitation leads to nanocrystallites of the order of 100–200&nbsp;nm in size and their sensitivity as X-ray storage phosphors is increased a remarkable ~500,000 times because of the specific arrangements and density of defect centers in comparison with microcrystalline samples prepared by sintering at high temperature.<ref>{{cite journal|last1=Liu|first1=Zhiqiang |last2=Stevens-Kalceff|first2=Marion |last3=Riesen|first3=Hans |title=Photoluminescence and Cathodoluminescence Properties of Nanocrystalline BaFCl:Sm3+ X-ray Storage Phosphor|journal=Journal of Physical Chemistry C|date=2012-03-16|volume=116|issue=14 |pages=8322–8331|doi=10.1021/jp301338b}}</ref> The mechanism is based on reduction of Sm{{sup|3+}} to Sm{{sup|2+}} by trapping electrons that are created upon exposure to ionizing radiation in the BaFCl host. The {{sup|5}}D{{sub|J}}–{{sup|7}}F{{sub|J}} f–f luminescence lines can be very efficiently excited via the parity allowed 4f{{sup|6}}→4f{{sup|5}}5d transition at ~417&nbsp;nm. The latter wavelength is ideal for efficient excitation by blue-violet laser diodes as the transition is electric dipole allowed and thus relatively intense (400 L/(mol⋅cm)).<ref>{{cite journal|last1=Wang|first1=Xianglei |last2=Liu|first2=Zhiqiang |last3=Stevens-Kalceff|first3=Marion |last4=Riesen|first4=Hans |title=Mechanochemical Preparation of Nanocrystalline BaFCl Doped with Samarium in the 2+ Oxidation State|journal=Inorganic Chemistry|date=August 12, 2014 |volume=53|issue=17|pages=8839–8841 |doi=10.1021/ic500712b|pmid=25113662}}</ref>
The phosphor has potential applications in personal dosimetry, dosimetry and imaging in radiotherapy, and medical imaging.<ref>{{cite web|title=Dosimetry&Imaging Pty Ltd|url=http://www.oelimaging.com |access-date=2018-11-28|archive-url= https://web.archive.org/web/20170926094926/http://oelimaging.com/ |archive-date=2017-09-26}}</ref>

===Non-commercial and potential uses===

* The change in electrical resistivity in [[samarium monochalcogenides]] can be used in a pressure sensor or in a memory device triggered between a low-resistance and high-resistance state by external pressure,<ref>{{Cite patent|number=20100073997|title=Piezo-Driven Non-Volatile Memory Cell with Hysteretic Resistance|gdate=2010-03-25|invent1=Elmegreen|invent2=Krusin-elbaum|invent3=Liu|invent4=Martyna|inventor1-first=Bruce G.|inventor2-first=Lia|inventor3-first=Xiao Hu|inventor4-first=Glenn J.|url=https://www.freepatentsonline.com/y2010/0073997.html}}</ref> and such devices are being developed commercially.<ref>{{Cite web |title=About us |url=https://tenzo-sms.ru/en/about |access-date=2022-12-31 |website=tenzo-sms.ru}}</ref> Samarium monosulfide also generates electric voltage upon moderate heating to about {{convert|150|C|F}} that can be applied in [[Thermoelectric generator|thermoelectric power converters]].<ref>{{cite journal|last1=Kaminskii|first1=V. V. |last2=Solov'ev |first2=S. M. |last3=Golubkov|first3=A. V.|title=Electromotive Force Generation in Homogeneously Heated Semiconducting Samarium Monosulfide |doi=10.1134/1.1467284 |date=2002 |page=229 |volume=28 |journal=Technical Physics Letters |url=http://www.tenzo-sms.ru/en/articles/5 |issue=3 |bibcode=2002TePhL..28..229K |s2cid=122463906 |archive-url=https://web.archive.org/web/20120315180549/http://www.tenzo-sms.ru/en/articles/5 |archive-date=2012-03-15}}</ref>
* Analysis of relative concentrations of samarium and neodymium isotopes {{sup|147}}Sm, {{sup|144}}Nd, and {{sup|143}}Nd allows determination of the age and origin of rocks and meteorites in [[samarium–neodymium dating]]. Both elements are lanthanides and are very similar physically and chemically. Thus, Sm–Nd dating is either insensitive to partitioning of the marker elements during various geologic processes, or such partitioning can well be understood and modeled from the [[ionic radius|ionic radii]] of said elements.<ref>Bowen, Robert and Attendorn, H -G [https://books.google.com/books?id=k90iAnFereYC&pg=PA270 ''Isotopes in the Earth Sciences''], Springer, 1988, {{ISBN|0-412-53710-9}}, pp. 270 ff</ref>
* The Sm{{sup|3+}} ion is a potential [[Activator (phosphor)|activator]] for use in warm-white light emitting diodes. It offers high [[luminous efficacy]] due to narrow emission bands; but the generally low [[quantum efficiency]] and too little absorption in the [[Ultraviolet#Subtypes|UV-A]] to blue spectral region hinders commercial application.<ref>{{cite journal|last1=Baur|first1=F.|last2=Katelnikovas|first2=A. |last3=Sazirnakovas|first3=S. |last4=Jüstel|first4=T. |title=Synthesis and Optical Properties of Li{{sub|3}}Ba{{sub|2}}La{{sub|3}}(MoO{{sub|4}}){{sub|8}}:Sm{{sup|3+}} |journal=Zeitschrift für Naturforschung B |volume=69|pages=183–192 |date=2014|doi=10.5560/ZNB.2014-3279|issue=2|s2cid=197099937}}</ref>
* Samarium is used for [[ionosphere]] testing. A rocket spreads samarium monoxide as a red vapor at high altitude, and researchers test how the atmosphere disperses it and how it impacts radio transmissions.<ref>{{cite journal |last1=Caton |first1=Ronald G. |last2=Pedersen |first2=Todd R. |last3=Groves |first3=Keith M. |last4=Hines |first4=Jack |last5=Cannon |first5=Paul S. |last6=Jackson-Booth |first6=Natasha |last7=Parris |first7=Richard T. |last8=Holmes |first8=Jeffrey M. |last9=Su |first9=Yi-Jiun |last10=Mishin |first10=Evgeny V. |last11=Roddy |first11=Patrick A. |last12=Viggiano |first12=Albert A. |last13=Shuman |first13=Nicholas S. |last14=Ard |first14=Shaun G. |last15=Bernhardt |first15=Paul A. |last16=Siefring |first16=Carl L. |last17=Retterer |first17=John |last18=Kudeki |first18=Erhan |last19=Reyes |first19=Pablo M. |title=Artificial ionospheric modification: The Metal Oxide Space Cloud experiment |journal=Radio Science |date=May 2017 |volume=52 |issue=5 |pages=539–558 |doi=10.1002/2016rs005988|url=https://pure-oai.bham.ac.uk/ws/files/40897676/Caton_et_al_2017_Radio_Science.pdf |bibcode=2017RaSc...52..539C |s2cid=55195732 }}</ref><ref>{{cite web |last1=Zell |first1=Holly |title=First of Four Sounding Rockets Launched from the Marshall Islands |url=https://www.nasa.gov/mission_pages/sounding-rockets/news/mosc.html |website=NASA |language=en |date=2013-06-07 |access-date=2019-08-15 |archive-date=2021-10-11 |archive-url=https://web.archive.org/web/20211011040155/https://www.nasa.gov/mission_pages/sounding-rockets/news/mosc.html |url-status=dead }}</ref>
* Samarium hexaboride, {{chem2|SmB6}}, has recently been shown to be a [[topological insulator]] with potential uses in [[quantum computing]].<ref name="physorgsamarium">{{Cite journal |last1=Li |first1=G. |last2=Xiang |first2=Z. |last3=Yu |first3=F. |last4=Asaba |first4=T. |last5=Lawson |first5=B. |last6=Cai |first6=P. |last7=Tinsman |first7=C. |last8=Berkley |first8=A. |last9=Wolgast |first9=S. |last10=Eo |first10=Y. S. |last11=Kim |first11=Dae-Jeong |last12=Kurdak |first12=C. |last13=Allen |first13=J. W. |last14=Sun |first14=K. |last15=Chen |first15=X. H. |date=2014-12-05 |title=Two-dimensional Fermi surfaces in Kondo insulator SmB 6 |url=https://www.science.org/doi/10.1126/science.1250366 |journal=Science |language=en |volume=346 |issue=6214 |pages=1208–1212 |doi=10.1126/science.1250366 |pmid=25477456 |arxiv=1306.5221 |bibcode=2014Sci...346.1208L |s2cid=119191689 |issn=0036-8075}}</ref><ref>{{Cite journal|last1=Botimer|arxiv=1211.6769 |first1=J. |last2=Kim |first2=D. J. |last3=Thomas  |first3=S. |last4=Grant |first4=T. |last5=Fisk |first5=Z. |author6=Jing Xia |title=Robust Surface Hall Effect and Nonlocal Transport in SmB<sub>6</sub>: Indication for an Ideal Topological Insulator |journal=Scientific Reports |volume=3 |issue=3150 |pages=3150 |year=2013|doi=10.1038/srep03150 |bibcode=2013NatSR...3.3150K |pmid=24193196 |pmc=3818682}}</ref><ref>{{cite journal |last1=Zhang |first1=Xiaohang |last2=Butch |first2=N. P. |last3=Syers |first3=P. |last4=Ziemak |first4=S. |last5=Greene |first5=Richard L. |last6=Paglione |first6=Johnpierre |title=Hybridization, Correlation, and In-Gap States in the Kondo Insulator SmB<sub>6</sub> |year=2013 |doi=10.1103/PhysRevX.3.011011 |journal=Physical Review X |volume=3 |issue=1|pages=011011 |arxiv=1211.5532|bibcode=2013PhRvX...3a1011Z |s2cid=53638956 }}</ref><ref>{{Cite journal |arxiv=1211.5104 |first1=Steven |last1=Wolgast |first2=Cagliyan |last2=Kurdak |first3=Kai |last3=Sun |first4=J. W. |last4=Allen |first5=Dae-Jeong |last5=Kim |first6=Zachary |last6=Fisk |title=Low-temperature surface conduction in the Kondo insulator SmB<sub>6</sub>|journal=Physical Review B |volume=88 |issue=18 |pages=180405 |date=2012 |display-authors=3|doi=10.1103/PhysRevB.88.180405 |bibcode=2013PhRvB..88r0405W |s2cid=119242604 }}</ref>