Samarium, 62Sm
Pronunciation/səˈmɛəriəm/ (sə-MAIR-ee-əm)
Appearancesilvery white
Standard atomic weight Ar°(Sm)
  • 150.36±0.02
  • 150.36±0.02 (abridged)[1]
Samarium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Atomic number (Z)62
Groupf-block groups (no number)
Periodperiod 6
Block  f-block
Electron configuration[Xe] 4f6 6s2
Electrons per shell2, 8, 18, 24, 8, 2
Physical properties
Phase at STPsolid
Melting point1345 K ​(1072 °C, ​1962 °F)
Boiling point2173 K ​(1900 °C, ​3452 °F)
Density (near r.t.)7.52 g/cm3
when liquid (at m.p.)7.16 g/cm3
Heat of fusion8.62 kJ/mol
Heat of vaporization192 kJ/mol
Molar heat capacity29.54 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1001 1106 1240 (1421) (1675) (2061)
Atomic properties
Oxidation states0,[2] +1,[3] +2, +3 (a mildly basic oxide)
ElectronegativityPauling scale: 1.17
Ionization energies
  • 1st: 544.5 kJ/mol
  • 2nd: 1070 kJ/mol
  • 3rd: 2260 kJ/mol
Atomic radiusempirical: 180 pm
Covalent radius198±8 pm
Color lines in a spectral range
Spectral lines of samarium
Other properties
Natural occurrenceprimordial
Crystal structurerhombohedral
Rhombohedral crystal structure for samarium
Speed of sound thin rod2130 m/s (at 20 °C)
Thermal expansion(r.t.) (α, poly) 12.7 µm/(m⋅K)
Thermal conductivity13.3 W/(m⋅K)
Electrical resistivity(r.t.) (α, poly) 0.940 µΩ⋅m
Magnetic orderingparamagnetic[4]
Molar magnetic susceptibility+1860.0×10−6 cm3/mol (291 K)[5]
Young's modulusα form: 49.7 GPa
Shear modulusα form: 19.5 GPa
Bulk modulusα form: 37.8 GPa
Poisson ratioα form: 0.274
Vickers hardness410–440 MPa
Brinell hardness440–600 MPa
CAS Number7440-19-9
Namingafter the mineral samarskite (itself named after Vassili Samarsky-Bykhovets)
Discovery and first isolationLecoq de Boisbaudran (1879)
Isotopes of samarium
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
144Sm 3.08% stable
145Sm syn 340 d ε 145Pm
146Sm syn 6.8×107 y α 142Nd
147Sm 15.00% 1.06×1011 y α 143Nd
148Sm 11.25% 7×1015 y α 144Nd
149Sm 13.82% stable
150Sm 7.37% stable
151Sm syn 94.6 y β 151Eu
152Sm 26.74% stable
153Sm syn 46.284 h β 153Eu
154Sm 22.74% stable
 Category: Samarium
| references

Samarium is a chemical element with 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, monochalcogenides SmS, SmSe and SmTe, as well as samarium(II) iodide. The last compound is a common reducing agent in chemical synthesis. Samarium has no significant biological role, and some samarium salts are slightly toxic.[6][7]

Samarium was discovered in 1879 by French chemist Paul-Émile Lecoq de Boisbaudran and 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, albeit indirectly. Though classified as a rare-earth element, samarium is the 40th most abundant element in Earth's crust and more common than metals such as tin. 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 magnets, which have permanent magnetization second only to neodymium magnets; however, samarium compounds can withstand significantly higher temperatures, above 700 °C (1,292 °F), without losing their magnetic properties, due to the alloy's higher Curie point. The radioisotope samarium-153 is the active component of the drug samarium (153Sm) 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 rods of nuclear reactors. 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 reactions, radioactive dating and X-ray lasers.

Physical properties

Samarium is a rare earth element with hardness and density similar to zinc. With a boiling point of 1,794 °C (3,261 °F), samarium is the third most volatile lanthanide after ytterbium and europium; this helps separation of samarium from ore. At ambient conditions, samarium normally has a rhombohedral structure (α form). Upon heating to 731 °C (1,348 °F), its crystal symmetry changes to hexagonal close-packed (hcp), but transition temperature depends on metal purity. Further heating to 922 °C (1,692 °F) transforms the metal into a body-centered cubic (bcc) phase. Heating to 300 °C (572 °F) plus compression to 40 kbar results in a double-hexagonally close-packed structure (dhcp). Higher pressure of the order of hundreds or thousands of kilobars induces a series of phase transformations, in particular with a tetragonal phase appearing at about 900 kbar.[8] In one study, the dhcp phase could be produced without compression, using a nonequilibrium annealing regime with a rapid temperature change between about 400 °C (752 °F) and 700 °C (1,292 °F), confirming the transient character of this samarium phase. Also, thin films of samarium obtained by vapor deposition may contain the hcp or dhcp phases at ambient conditions.[8]

Samarium and its sesquioxide are paramagnetic at room temperature. Their corresponding effective magnetic moments, below 2 Bohr magnetons, are the third-lowest among lanthanides (and their oxides) after lanthanum and lutetium. The metal transforms to an antiferromagnetic state upon cooling to 14.8 K.[9][10] Individual samarium atoms can be isolated by encapsulating them into fullerene molecules.[11] They can also be doped between the C60 molecules in the fullerene solid, rendering it superconductive at temperatures below 8 K.[12] Samarium doping of iron-based superconductors – a class of high-temperature superconductor – allows enhancing their transition temperature to 56 K, which is the highest value achieved so far in this series.[13]

Chemical properties

Freshly prepared samarium has a silvery luster. In air, it slowly oxidizes at room temperature and spontaneously ignites at 150 °C (302 °F).[7][14] Even when stored under mineral oil, samarium gradually oxidizes and develops a grayish-yellow powder of the oxide-hydroxide mixture at the surface. The metallic appearance of a sample can be preserved by sealing it under an inert gas such as argon.

Samarium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form samarium hydroxide:[15]

2Sm(s) + 6H2O(l) → 2Sm(OH)3(aq) + 3H2(g)

Samarium dissolves readily in dilute sulfuric acid to form solutions containing the yellow[16] to pale green Sm(III) ions, which exist as [Sm(OH2)9]3+ complexes:[15]

2Sm(s) + 3H2SO4(aq) → 2Sm3+(aq) + 3SO2−4(aq) + 3H2(g)

Samarium is one of the few lanthanides that exhibit the +2 oxidation state. Sm2+ ions are blood-red in aqueous solution.[17]


Main article: Samarium compounds


The most stable oxide of samarium is the sesquioxide Sm2O3. Like many samarium compounds, it exists in several crystalline phases. The trigonal form is obtained by slow cooling from the melt. The melting point of Sm2O3 is high (2345 °C), so it is usually melted not by direct heating, but with induction heating, through a radio-frequency coil. Sm2O3 crystals of monoclinic symmetry can be grown by the flame fusion method (Verneuil process) from Sm2O3 powder, that yields cylindrical boules up to several centimeters long and about one centimeter in diameter. The boules are transparent when pure and defect-free and are orange otherwise. Heating the metastable trigonal Sm2O3 to 1,900 °C (3,450 °F) converts it to the more stable monoclinic phase.[20] Cubic Sm2O3 has also been described.[21]

Samarium is one of the few lanthanides that form a monoxide, SmO. This lustrous golden-yellow compound was obtained by reducing Sm2O3 with samarium metal at high temperature (1000 °C) and pressure above 50 kbar; lowering the pressure resulted in incomplete reaction. SmO has cubic rock-salt lattice structure.[19][39]


See also: Samarium monochalcogenides

Samarium forms a trivalent sulfide, selenide and telluride. Divalent chalcogenides SmS, SmSe and SmTe with cubic rock-salt crystal structure are also known. These chalcogenides convert from semiconducting to metallic state at room temperature upon application of pressure. Whereas the transition is continuous and occurs at about 20–30 kbar in SmSe and SmTe, it is abrupt in SmS and requires only 6.5 kbar. This effect results in spectacular color change in SmS from black to golden yellow when its crystals of films are scratched or polished. The transition does not change lattice symmetry, but there is a sharp decrease (~15%) in the crystal volume.[40] It exhibits hysteresis, i.e., when the pressure is released, SmS returns to the semiconducting state at a much lower pressure of about 0.4 kbar.[7][41]


Samarium metal reacts with all the halogens, forming trihalides:[42]

2 Sm (s) + 3 X2 (g) → 2 SmX3 (s) (X = F, Cl, Br or I)

Their further reduction with samarium, lithium or sodium metals at elevated temperatures (about 700–900 °C) yields dihalides.[32] The diiodide can also be prepared by heating SmI3, or by reacting the metal with 1,2-diiodoethane in anhydrous tetrahydrofuran at room temperature:[43]

Sm (s) + ICH2-CH2I → SmI2 + CH2=CH2.

In addition to dihalides, the reduction also produces many non-stoichiometric samarium halides with a well-defined crystal structure, such as Sm3F7, Sm14F33, Sm27F64,[31] Sm11Br24, Sm5Br11 and Sm6Br13.[44]

As reflected in the table above, samarium halides change their crystal structures when one type of halide anion is substituted for another, which is an uncommon behavior for most elements (e.g. actinides). Many halides have two major crystal phases for one composition, one being significantly more stable and another being metastable. The latter is formed upon compression or heating, followed by quenching to ambient conditions. For example, compressing the usual monoclinic samarium diiodide and releasing the pressure results in a PbCl2-type orthorhombic structure (density 5.90 g/cm3),[45] and similar treatment results in a new phase of samarium triiodide (density 5.97 g/cm3).[46]


Sintering powders of samarium oxide and boron, in vacuum, yields a powder containing several samarium boride phases, and their volume ratio can be controlled through the mixing proportion.[47] The powder can be converted into larger crystals of a certain samarium boride using arc melting or zone melting techniques, relying on the different melting/crystallization temperature of SmB6 (2580 °C), SmB4 (about 2300 °C) and SmB66 (2150 °C). All these materials are hard, brittle, dark-gray solids with the hardness increasing with the boron content.[27] Samarium diboride is too volatile to be produced with these methods and requires high pressure (about 65 kbar) and low temperatures between 1140 and 1240 °C to stabilize its growth. Increasing the temperature results in the preferential formations of SmB6.[25]

Samarium hexaboride

Samarium hexaboride is a typical intermediate-valence compound where samarium is present both as Sm2+ and Sm3+ ions in a 3:7 ratio.[47] It belongs to a class of Kondo insulators, that is at high temperatures (above 50 K), its properties are typical of a Kondo metal, with metallic electrical conductivity characterized by strong electron scattering, whereas at low temperatures, it behaves as a non-magnetic insulator with a narrow band gap of about 4–14 meV.[48] The cooling-induced metal-insulator transition in SmB6 is accompanied by a sharp increase in the thermal conductivity, peaking at about 15 K. The reason for this increase is that electrons themselves do not contribute to the thermal conductivity at low temperatures, which is dominated by phonons, but the decrease in electron concentration reduced the rate of electron-phonon scattering.[49] New research seems to show that it may be a topological insulator.[50][51][52]

Other inorganic compounds

Samarium sulfate, Sm2(SO4)3
Samarium sulfate, Sm2(SO4)3

Samarium carbides are prepared by melting a graphite-metal mixture in an inert atmosphere. After the synthesis, they are unstable in air and are studied also under inert atmosphere.[29] Samarium monophosphide SmP is a semiconductor with the bandgap of 1.10 eV, the same as in silicon, and high electrical conductivity of n-type. It can be prepared by annealing at 1,100 °C (2,010 °F) an evacuated quartz ampoule containing mixed powders of phosphorus and samarium. Phosphorus is highly volatile at high temperatures and may explode, thus the heating rate has to be kept well below 1 °C/min.[37] Similar procedure is adopted for the monarsenide SmAs, but the synthesis temperature is higher at 1,800 °C (3,270 °F).[38]

Numerous crystalline binary compounds are known for samarium and one of the group 14, 15, or 16 elements X, where X is Si, Ge, Sn, Pb, Sb or Te, and metallic alloys of samarium form another large group. They are all prepared by annealing mixed powders of the corresponding elements. Many of the resulting compounds are non-stoichiometric and have nominal compositions SmaXb, where the b/a ratio varies between 0.5 and 3.[53][54]

Organometallic compounds

Samarium forms a cyclopentadienide Sm(C5H5)3 and its chloroderivatives Sm(C5H5)2Cl and Sm(C5H5)Cl2. They are prepared by reacting samarium trichloride with NaC5H5 in tetrahydrofuran. Contrary to cyclopentadienides of most other lanthanides, in Sm(C5H5)3 some C5H5 rings bridge each other by forming ring vertexes η1 or edges η2 toward another neighboring samarium, thus creating polymeric chains.[17] The chloroderivative Sm(C5H5)2Cl has a dimer structure, which is more accurately expressed as (η(5)−C5H5)2Sm(−Cl)2(η(5)−C5H5)2. There, the chlorine bridges can be replaced, for instance, by iodine, hydrogen or nitrogen atoms or by CN groups.[55]

The (C5H5) ion in samarium cyclopentadienides can be replaced by the indenide (C9H7) or cyclooctatetraenide (C8H8)2− ring, resulting in Sm(C9H7)3 or KSm(η(8)−C8H8)2. The latter compound has a structure similar to uranocene. There is also a cyclopentadienide of divalent samarium, Sm(C5H5)2− a solid that sublimates at about 85 °C (185 °F). Contrary to ferrocene, the C5H5 rings in Sm(C5H5)2 are not parallel but are tilted by 40°.[55][56]

A metathesis reaction in tetrahydrofuran or ether gives alkyls and aryls of samarium:[55]

SmCl3 + 3LiR → SmR3 + 3LiCl
Sm(OR)3 + 3LiCH(SiMe3)2 → Sm{CH(SiMe3)2}3 + 3LiOR

Here R is a hydrocarbon group and Me = methyl.


Main article: Isotopes of samarium

Naturally occurring samarium is composed of five stable isotopes: 144Sm, 149Sm, 150Sm, 152Sm and 154Sm, and two extremely long-lived radioisotopes, 147Sm (half-life t1/2 = 1.06×1011 years) and 148Sm (7×1015 years), with 152Sm being the most abundant (26.75%).[57] 149Sm is listed by various sources either as stable[57][58] or radioactive,[59] but only a lower bound for its half-life is given. Some observationally stable samarium isotopes are predicted to decay to isotopes of neodymium.[60] The long-lived isotopes 146Sm, 147Sm, and 148Sm undergo alpha decay to neodymium isotopes. Lighter unstable isotopes of samarium mainly decay by electron capture to promethium, while heavier ones beta decay to europium.[57] Natural samarium has a radioactivity of 127 Bq/g, mostly due to 147Sm,[61] which alpha decays to 143Nd with a half-life of 1.06×1011 years and is used in samarium–neodymium dating.[62][63] 146Sm can be used as an extinct radionuclide in radiometric dating.[64][65] The known isotopes range from 129Sm to 168Sm.[57][66] The half-lives of 151Sm and 145Sm are 90 years and 340 days, respectively. All remaining radioisotopes have half-lives that are less than 2 days, and most these have half-life less than 48 seconds. Samarium also has twelve known nuclear isomers, the most stable of which are 141mSm (half-life 22.6 minutes), 143m1Sm (t1/2 = 66 seconds), and 139mSm (t1/2 = 10.7 seconds).[57]


Paul Émile Lecoq de Boisbaudran, the discoverer of samarium
Paul Émile Lecoq de Boisbaudran, the discoverer of samarium

Detection of samarium and related elements was announced by several scientists in the second half of the 19th century; however, most sources give priority to French chemist Paul-Émile Lecoq de Boisbaudran.[67][68] Boisbaudran isolated samarium oxide and/or hydroxide in Paris in 1879 from the mineral samarskite ((Y,Ce,U,Fe)3(Nb,Ta,Ti)5O16) and identified a new element in it via sharp optical absorption lines.[14] Swiss chemist Marc Delafontaine announced a new element decipium (from Latin: decipiens meaning "deceptive, misleading") in 1878,[69][70] but later in 1880–1881 demonstrated that it was a mix of several elements, one being identical to Boisbaudran's samarium.[71][72] Though samarskite was first found in the Ural Mountains in Russia, by the late 1870s it had been found in other places, making it available to many researchers. In particular, it was found that the samarium isolated by Boisbaudran was also impure and had a comparable amount of europium. The pure element was produced only in 1901 by Eugène-Anatole Demarçay.[73][74][75][76][77]

Boisbaudran named his element samarium after the mineral samarskite, which in turn honored Vassili Samarsky-Bykhovets (1803–1870). Samarsky-Bykhovets, as the Chief of Staff of the Russian Corps of Mining Engineers, had granted access for two German mineralogists, the brothers Gustav and Heinrich Rose, to study the mineral samples from the Urals.[78][79][80] Samarium was thus the first chemical element to be named after a person.[73][81] The word samaria is sometimes used to mean samarium(III) oxide, by analogy with yttria, zirconia, alumina, ceria, holmia, etc. The symbol Sm was suggested for samarium, but an alternative Sa was often used instead until the 1920s.[73][82]

Before the advent of ion-exchange separation technology in the 1950s, pure samarium had no commercial uses. However, a by-product of fractional crystallization purification of neodymium was a mix of samarium and gadolinium that got the name "Lindsay Mix" after the company that made it. This material is thought to have been used for nuclear control rods in some early nuclear reactors. Nowadays, a similar commodity product has the name "samarium-europium-gadolinium" (SEG) concentrate.[81] It is prepared by solvent extraction from the mixed lanthanides isolated from bastnäsite (or monazite). Since heavier lanthanides have more affinity for the solvent used, they are easily extracted from the bulk using relatively small proportions of solvent. Not all rare-earth producers who process bastnäsite do so on a large enough scale to continue by separating the components of SEG, which typically makes up only 1–2% of the original ore. Such producers therefore make SEG with a view to marketing it to the specialized processors. In this manner, the valuable europium in the ore is rescued for use in making phosphor. Samarium purification follows the removal of the europium. As of 2012, being in oversupply, samarium oxide is cheaper on a commercial scale than its relative abundance in the ore might suggest.[83]

Occurrence and production


With the average concentration of about 8 parts per million (ppm), samarium is the 40th most abundant element in the Earth's crust. It is the fifth most abundant lanthanide and has a higher concentration than many other elements such as tin (which has an average concentration of 2 ppm). Samarium concentration in soils varies between 2 and 23 ppm, and oceans contain about 0.5–0.8 parts per trillion.[7] Distribution of samarium in soils strongly depends on its chemical state and is very inhomogeneous: in sandy soils, samarium concentration is about 200 times higher at the surface of soil particles than in the water trapped between them, and this ratio can exceed 1,000 in clays.[84]

Samarium is not found free in nature, but, like other rare earth elements, is contained in many minerals, including monazite, bastnäsite, cerite, gadolinite and samarskite; monazite (in which samarium occurs at concentrations of up to 2.8%)[14] and bastnäsite are mostly used as commercial sources. World resources of samarium are estimated at two million tonnes; they are mostly located in China, US, Brazil, India, Sri Lanka and Australia, and the annual production is about 700 tonnes.[7] Country production reports are usually given for all rare-earth metals combined. By far, China has the largest production with 120,000 tonnes mined per year; it is followed by the US (about 5,000 tonnes)[84] and India (2,700 tonnes).[85] Samarium is usually sold as oxide, which at the price of about US$30/kg is one of the cheapest lanthanide oxides.[83] Whereas mischmetal – a mixture of rare earth metals containing about 1% of samarium – has long been used, relatively pure samarium has been isolated only recently, through ion exchange processes, solvent extraction techniques, and electrochemical deposition. The metal is often prepared by electrolysis of a molten mixture of samarium(III) chloride with sodium chloride or calcium chloride. Samarium can also be obtained by reducing its oxide with lanthanum. The product is then distilled to separate samarium (boiling point 1794 °C) and lanthanum (b.p. 3464 °C).[68]

Very few minerals have samarium being the most dominant element. Minerals with essential (dominant) samarium include monazite-(Sm) and florencite-(Sm). These minerals are very rare and are usually found containing other elements, usually cerium or neodymium.[86][87][88][89]

Samarium-151 is produced in nuclear fission of uranium with a yield of about 0.4% of all fissions. It is also made by neutron capture by samarium-149, which is added to the control rods of nuclear reactors. Therefore, 151Sm is present in spent nuclear fuel and radioactive waste.[84]


Barbier reaction using SmI2
Barbier reaction using SmI2

One of the most important uses of samarium is samarium–cobalt magnets, which are nominally SmCo5 or Sm2Co17. They have high permanent magnetization, about 10,000 times that of iron and second only to neodymium magnets. However, samarium magnets resist demagnetization better; they are stable to temperatures above 700 °C (1,292 °F) (cf. 300–400 °C for neodymium magnets). These magnets are found in small motors, headphones, and high-end magnetic pickups for guitars and related musical instruments.[7] For example, they are used in the motors of a solar-powered electric aircraft, the Solar Challenger, and in the Samarium Cobalt Noiseless electric guitar and bass pickups.

Another important use of samarium and its compounds is as catalyst and chemical reagent. Samarium catalysts help decomposition of plastics, dechlorination of pollutants such as polychlorinated biphenyls (PCB), as well as dehydration and dehydrogenation of ethanol.[14] Samarium(III) triflate Sm(OTf)3, that is Sm(CF3SO3)3, is one of the most efficient Lewis acid catalysts for a halogen-promoted Friedel–Crafts reaction with alkenes.[90] Samarium(II) iodide is a very common reducing and coupling agent in organic synthesis, for example in desulfonylation reactions; annulation; Danishefsky, Kuwajima, Mukaiyama and Holton Taxol total syntheses; strychnine total synthesis; Barbier reaction and other reductions with samarium(II) iodide.[91] Samarium hexaboride, SmB6, has recently been shown to be a topological insulator with potential uses in quantum computing.[92]

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 "flint" ignition device of many lighters and torches.[7][14]

Chemical structure of Sm-EDTMP
Chemical structure of Sm-EDTMP

Samarium-153 is a beta emitter with half-life 46.3 hours. It is used to kill cancer cells in lung cancer, prostate cancer, breast cancer, and osteosarcoma. For this purpose, samarium-153 is chelated with ethylene diamine tetramethylene phosphonate (EDTMP) and injected intravenously. The chelation prevents accumulation of radioactive samarium in the body that would result in excessive irradiation and generation of new cancer cells.[7] The corresponding drug has several names including samarium (153Sm) lexidronam; its trade name is Quadramet.[93][94][95]

Samarium-149 has a high cross section for neutron capture (41,000 barns) and so is used in control rods of nuclear reactors. Its advantage compared to competing materials, such as boron and cadmium, is stability of absorption – most of the fusion products of 149Sm are other isotopes of samarium that are also good neutron absorbers. For example, the cross section of samarium-151 is 15,000 barns, it is on the order of hundreds of barns for 150Sm, 152Sm, and 153Sm, and 6,800 barns for natural (mixed-isotope) samarium.[14][84][96] Among the decay products in a nuclear reactor, 149Sm is regarded as the second most important for the reactor design and operation after xenon-135.[97]

Non-commercial and potential uses

Samarium-doped calcium fluoride crystals were used as an active medium in one of the first solid-state lasers 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 nm. It had to be cooled by liquid helium and so did not find practical applications.[98][99]

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 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 mJ. The active medium was samarium plasma produced by irradiating samarium-coated glass with a pulsed infrared Nd-glass laser (wavelength ~1.05 μm).[100]

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,[101] and such devices are being developed commercially.[102] Samarium monosulfide also generates electric voltage upon moderate heating to about 150 °C (302 °F) that can be applied in thermoelectric power converters.[103]

Analysis of relative concentrations of samarium and neodymium isotopes 147Sm, 144Nd, and 143Nd allows determination of 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 radii of said elements.[104]

Sm3+ ion is a potential activator for use in warm-white light emitting diodes. It offers high luminous efficacy due to the narrow emission bands; but the generally low quantum efficiency and too little absorption in the UV-A to blue spectral region hinders commercial application.[105]

In recent years it has been shown that nanocrystalline BaFCl:Sm3+ as prepared by co-precipitation can serve as a very efficient x-ray storage phosphor.[106] The co-precipitation leads to nanocrystallites of the order of 100-200 nm in size and their sensitivity as x-ray storage phosphors is increased an astounding ∼500,000 times because of the specific arrangements and density of defect centers in comparison with microcrystalline samples prepared by sintering at high temperature.[107] The mechanism is based on reduction of Sm3+ to Sm2+ by trapping electrons that are created upon exposure to ionizing radiation in the BaFCl host. The 5 DJ-7 FJ f-f luminescence lines can be very efficiently excited via the parity allowed 4f6 →4f5 5d transition at ~417 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)).[108] The phosphor has potential applications in personal dosimetry, dosimetry and imaging in radiotherapy, and medical imaging.[109]

Samarium is used for ionosphere testing. A rocket spreads it as a red vapor at high altitude, and researchers tests how the atmosphere disperses it and how it impacts radio transmissions.[110][111]

Biological role and precautions

GHS labelling:
GHS02: Flammable
GHS08: Health hazard
H228, H261, H373
P210, P231+P232, P422[112]
NFPA 704 (fire diamond)

Samarium salts stimulate metabolism, but it is unclear whether this is from samarium or other lanthanides present with it. The total amount of samarium in adults is about 50 μg, mostly in liver and kidneys and with ~8 μg/L being dissolved in blood. Samarium is not absorbed by plants to a measurable concentration and so is normally not part of human diet. However, a few plants and vegetables may contain up to 1 part per million of samarium. Insoluble salts of samarium are non-toxic and the soluble ones are only slightly toxic.[7][6]

When ingested, only ~0.05% of samarium salts is absorbed into the bloodstream and the remainder is excreted. From the blood, ~45% goes to the liver and 45% is deposited on the surface of the bones where it remains for ~10 years; the balance 10% is excreted.[84]


  1. ^ "Standard Atomic Weights: Samarium". CIAAW. 2005.
  2. ^ Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (2003-12-15). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.
  3. ^ SmB6- cluster anion has been reported and contains Sm in rare oxidation state of +1; see Paul, J. Robinson; Xinxing, Zhang; Tyrel, McQueen; Kit, H. Bowen; Anastassia, N. Alexandrova (2017). "SmB6 Cluster Anion: Covalency Involving f Orbitals". J. Phys. Chem. A 2017, 121, 8, 1849–1854. 121 (8): 1849–1854..
  4. ^ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  5. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  6. ^ a b Bayouth, J. E.; Macey, D. J.; Kasi, L. P.; Fossella, F. V. (1994). "Dosimetry and toxicity of samarium-153-EDTMP administered for bone pain due to skeletal metastases". Journal of Nuclear Medicine. 35 (1): 63–69. PMID 7505819.
  7. ^ a b c d e f g h i Emsley, John (2001). "Samarium". Nature's Building Blocks: An A–Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 371–374. ISBN 0-19-850340-7.
  8. ^ a b c d Shi, N.; Fort, D. (1985). "Preparation of samarium in the double hexagonal close packed form". Journal of the Less Common Metals. 113 (2): 21. doi:10.1016/0022-5088(85)90294-2.
  9. ^ Lock, J. M. (1957). "The Magnetic Susceptibilities of Lanthanum, Cerium, Praseodymium, Neodymium and Samarium, from 1.5 K to 300 K". Proceedings of the Physical Society. Series B. 70 (6): 566. Bibcode:1957PPSB...70..566L. doi:10.1088/0370-1301/70/6/304.
  10. ^ Huray, P.; Nave, S.; Haire, R. (1983). "Magnetism of the heavy 5f elements". Journal of the Less Common Metals. 93 (2): 293. doi:10.1016/0022-5088(83)90175-3.
  11. ^ Okazaki, T.; Suenaga, Kazutomo; Hirahara, Kaori; et al. (2002). "Electronic and geometric structures of metallofullerene peapods". Physica B. 323 (1–4): 97. Bibcode:2002PhyB..323...97O. doi:10.1016/S0921-4526(02)00991-2.
  12. ^ Chen, X.; Roth, G. (1995). "Superconductivity at 8 K in samarium-doped C60". Physical Review B. 52 (21): 15534–15536. Bibcode:1995PhRvB..5215534C. doi:10.1103/PhysRevB.52.15534. PMID 9980911.
  13. ^ Wu, G.; Xie, Y. L.; Chen, H.; et al. (2008). "Superconductivity at 56 K in Samarium-doped SrFeAsF". Journal of Physics: Condensed Matter. 21 (14): 142203. arXiv:0811.0761. Bibcode:2009JPCM...21n2203W. doi:10.1088/0953-8984/21/14/142203. PMID 21825317. S2CID 41728130.
  14. ^ a b c d e f Hammond, C. R. (2004-06-29). "The Elements". Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN 0-8493-0485-7.
  15. ^ a b "Chemical reactions of Samarium". Webelements. Retrieved 2009-06-06.
  16. ^ Greenwood, p. 1243
  17. ^ a b Greenwood, p. 1248
  18. ^ Vohra, Y.; Akella, Jagannadham; Weir, Sam; Smith, Gordon S. (1991). "A new ultra-high pressure phase in samarium". Physics Letters A. 158 (1–2): 89. Bibcode:1991PhLA..158...89V. doi:10.1016/0375-9601(91)90346-A.
  19. ^ a b Leger, J.; Yacoubi, N.; Loriers, J. (1981). "Synthesis of rare earth monoxides". Journal of Solid State Chemistry. 36 (3): 261. Bibcode:1981JSSCh..36..261L. doi:10.1016/0022-4596(81)90436-9.
  20. ^ a b c Gouteron, J.; Michel, D.; Lejus, A. M.; Zarembowitch, J. (1981). "Raman spectra of lanthanide sesquioxide single crystals: Correlation between A and B-type structures". Journal of Solid State Chemistry. 38 (3): 288. Bibcode:1981JSSCh..38..288G. doi:10.1016/0022-4596(81)90058-X.
  21. ^ a b Taylor, D. (1984). "Thermal Expansion Data: III Sesquioxides, M2O3, with the corundum and the A-, B- and C-M2O3 structures". British Ceramic Transactions and Journal. 83 (4): 92–98.
  22. ^ Daou, J.; Vajda, P.; Burger, J. (1989). "Low temperature thermal expansion in SmH2+x". Solid State Communications. 71 (12): 1145. Bibcode:1989SSCom..71.1145D. doi:10.1016/0038-1098(89)90728-X.
  23. ^ Dolukhanyan, S. (1997). "Synthesis of novel compounds by hydrogen combustion". Journal of Alloys and Compounds. 253–254: 10. doi:10.1016/S0925-8388(96)03071-X.
  24. ^ Zavalii, L. V.; Kuz'ma, Yu. B.; Mikhalenko, S. I. (1990). "Sm2B5 boride and its structure". Soviet Powder Metallurgy and Metal Ceramics. 29 (6): 471. doi:10.1007/BF00795346. S2CID 138416728.
  25. ^ a b Cannon, J.; Cannon, D.; Tracyhall, H. (1977). "High pressure syntheses of SmB2 and GdB12". Journal of the Less Common Metals. 56: 83. doi:10.1016/0022-5088(77)90221-1.
  26. ^ Etourneau, J.; Mercurio, J.; Berrada, A.; Hagenmuller, P.; Georges, R.; Bourezg, R.; Gianduzzo, J. (1979). "The magnetic and electrical properties of some rare earth tetraborides". Journal of the Less Common Metals. 67 (2): 531. doi:10.1016/0022-5088(79)90038-9.
  27. ^ a b Solovyev, G. I.; Spear, K. E. (1972). "Phase Behavior in the Sm-B System". Journal of the American Ceramic Society. 55 (9): 475. doi:10.1111/j.1151-2916.1972.tb11344.x.
  28. ^ Schwetz, K.; Ettmayer, P.; Kieffer, R.; Lipp, A. (1972). "Über die Hektoboridphasen der Lanthaniden und Aktiniden". Journal of the Less Common Metals. 26: 99. doi:10.1016/0022-5088(72)90012-4.
  29. ^ a b c Spedding, F. H.; Gschneidner, K.; Daane, A. H. (1958). "The Crystal Structures of Some of the Rare Earth Carbides". Journal of the American Chemical Society. 80 (17): 4499. doi:10.1021/ja01550a017.
  30. ^ a b c d e f g h Greenwood, p. 1241
  31. ^ a b c d Greis, O. (1978). "Über neue Verbindungen im system SmF2_SmF3". Journal of Solid State Chemistry. 24 (2): 227. Bibcode:1978JSSCh..24..227G. doi:10.1016/0022-4596(78)90013-0.
  32. ^ a b Meyer, G.; Schleid, T. (1986). "The metallothermic reduction of several rare-earth trichlorides with lithium and sodium". Journal of the Less Common Metals. 116: 187. doi:10.1016/0022-5088(86)90228-6.
  33. ^ Bärnighausen, H. (1973). Rev. Chim. Miner. 10: 77–92.((cite journal)): CS1 maint: untitled periodical (link)
  34. ^ Zachariasen, W. H. (1948). "Crystal chemical studies of the 5f-series of elements. I. New structure types". Acta Crystallographica. 1 (5): 265. doi:10.1107/S0365110X48000703.
  35. ^ Asprey, L. B.; Keenan, T. K.; Kruse, F. H. (1964). "Preparation and Crystal Data for Lanthanide and Actinide Triiodides" (PDF). Inorganic Chemistry. 3 (8): 1137. doi:10.1021/ic50018a015.
  36. ^ Brown, R.; Clark, N. J. (1974). "Composition limits and vaporization behaviour of rare earth nitrides". Journal of Inorganic and Nuclear Chemistry. 36 (11): 2507. doi:10.1016/0022-1902(74)80462-8.
  37. ^ a b Meng, J.; Ren, Yufang (1991). "Studies on the electrical properties of rare earth monophosphides". Journal of Solid State Chemistry. 95 (2): 346. Bibcode:1991JSSCh..95..346M. doi:10.1016/0022-4596(91)90115-X.
  38. ^ a b Beeken, R.; Schweitzer, J. (1981). "Intermediate valence in alloys of SmSe with SmAs". Physical Review B. 23 (8): 3620. Bibcode:1981PhRvB..23.3620B. doi:10.1103/PhysRevB.23.3620.
  39. ^ Greenwood, p. 1239
  40. ^ Beaurepaire, Eric (Ed.) Magnetism: a synchrotron radiation approach, Springer, 2006 ISBN 3-540-33241-3 p. 393
  41. ^ Jayaraman, A.; Narayanamurti, V.; Bucher, E.; Maines, R. (1970). "Continuous and Discontinuous Semiconductor-Metal Transition in Samarium Monochalcogenides Under Pressure". Physical Review Letters. 25 (20): 1430. Bibcode:1970PhRvL..25.1430J. doi:10.1103/PhysRevLett.25.1430.
  42. ^ Greenwood, pp. 1236, 1241
  43. ^ Greenwood, p. 1240
  44. ^ Baernighausen, H.; Haschke, John M. (1978). "Compositions and crystal structures of the intermediate phases in the samarium-bromine system". Inorganic Chemistry. 17: 18. doi:10.1021/ic50179a005.
  45. ^ Beck, H. P. (1979). "Hochdruckmodifikationen der Diiodide von Sr., Sm und Eu. Eine neue PbCl2-Variante?". Zeitschrift für anorganische und allgemeine Chemie. 459: 81. doi:10.1002/zaac.19794590108.
  46. ^ Beck, H. P.; Gladrow, E. (1979). "Zur Hochdruckpolymorphie der Seltenerd-Trihalogenide". Zeitschrift für anorganische und allgemeine Chemie. 453: 79. doi:10.1002/zaac.19794530610.
  47. ^ a b Nickerson, J.; White, R.; Lee, K.; Bachmann, R.; Geballe, T.; Hull, G. (1971). "Physical Properties of SmB6". Physical Review B. 3 (6): 2030. Bibcode:1971PhRvB...3.2030N. doi:10.1103/PhysRevB.3.2030.
  48. ^ Nyhus, P.; Cooper, S.; Fisk, Z.; Sarrao, J. (1995). "Light scattering from gap excitations and bound states in SmB6". Physical Review B. 52 (20): 14308–14311. Bibcode:1995PhRvB..5214308N. doi:10.1103/PhysRevB.52.R14308. PMID 9980746.
  49. ^ Sera, M.; Kobayashi, S.; Hiroi, M.; Kobayashi, N.; Kunii, S. (1996). "Thermal conductivity of RB6 (R=Ce, Pr, Nd, Sm, Gd) single crystals". Physical Review B. 54 (8): R5207–R5210. Bibcode:1996PhRvB..54.5207S. doi:10.1103/PhysRevB.54.R5207. PMID 9986570.
  50. ^ Botimer, J.; Kim; Thomas; Grant; Fisk; Jing Xia (2013). "Robust Surface Hall Effect and Nonlocal Transport in SmB6: Indication for an Ideal Topological Insulator". Scientific Reports. 3 (3150): 3150. arXiv:1211.6769. Bibcode:2013NatSR...3E3150K. doi:10.1038/srep03150. PMC 3818682. PMID 24193196.
  51. ^ Zhang, Xiaohang; Butch; Syers; Ziemak; Greene; Paglione (2013). "Hybridization, Correlation, and In-Gap States in the Kondo Insulator SmB6". Physical Review X. 3 (1): 011011. arXiv:1211.5532. Bibcode:2013PhRvX...3a1011Z. doi:10.1103/PhysRevX.3.011011. S2CID 53638956.
  52. ^ Wolgast, Steven; Kurdak, Cagliyan; Sun, Kai; et al. (2012). "Low-temperature surface conduction in the Kondo insulator SmB6". Physical Review B. 88 (18): 180405. arXiv:1211.5104. Bibcode:2013PhRvB..88r0405W. doi:10.1103/PhysRevB.88.180405. S2CID 119242604.
  53. ^ Gladyshevskii, E. I.; Kripyakevich, P. I. (1965). "Monosilicides of rare earth metals and their crystal structures". Journal of Structural Chemistry. 5 (6): 789. doi:10.1007/BF00744231. S2CID 93941853.
  54. ^ Smith, G. S.; Tharp, A. G.; Johnson, W. (1967). "Rare earth–germanium and –silicon compounds at 5:4 and 5:3 compositions". Acta Crystallographica. 22 (6): 940. doi:10.1107/S0365110X67001902.
  55. ^ a b c Greenwood, p. 1249
  56. ^ Evans, William J.; Hughes, Laura A.; Hanusa, Timothy P. (1986). "Synthesis and x-ray crystal structure of bis(pentamethylcyclopentadienyl) complexes of samarium and europium: (C5Me5)2Sm and (C5Me5)2Eu". Organometallics. 5 (7): 1285. doi:10.1021/om00138a001.
  57. ^ a b c d e Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  58. ^ "Chart of the nuclides". Brookhaven National Laboratory.
  59. ^ Holden, Norman E. "Table of the isotopes" in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  60. ^ Belli, P.; Bernabei, R.; Danevich, F. A.; Incicchitti, A.; Tretyak, V. I. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (140): 4–6. arXiv:1908.11458. Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. S2CID 201664098.
  61. ^ Radiation Protection and NORM Residue Management in the Production of Rare Earths from Thorium Containing Minerals (PDF) (Report). Safety Report Series. International Atomic Energy Agency. p. 174. Retrieved 25 July 2022.
  62. ^ Depaolo, D. J.; Wasserburg, G. J. (1976). "Nd isotopic variations and petrogenetic models" (PDF). Geophysical Research Letters. 3 (5): 249. Bibcode:1976GeoRL...3..249D. doi:10.1029/GL003i005p00249.
  63. ^ McCulloch, M. T.; Wasserburg, G. J. (1978). "Sm-Nd and Rb-Sr Chronology of Continental Crust Formation". Science. 200 (4345): 1003–11. Bibcode:1978Sci...200.1003M. doi:10.1126/science.200.4345.1003. PMID 17740673. S2CID 40675318.
  64. ^ Samir Maji; et al. (2006). "Separation of samarium and neodymium: a prerequisite for getting signals from nuclear synthesis". Analyst. 131 (12): 1332–1334. Bibcode:2006Ana...131.1332M. doi:10.1039/b608157f. PMID 17124541.
  65. ^ Kinoshita, N.; Paul, M.; Kashiv, Y.; Collon, P.; Deibel, C. M.; DiGiovine, B.; Greene, J. P.; Henderson, D. J.; Jiang, C. L.; Marley, S. T.; Nakanishi, T.; Pardo, R. C.; Rehm, K. E.; Robertson, D.; Scott, R.; Schmitt, C.; Tang, X. D.; Vondrasek, R.; Yokoyama, A. (30 March 2012). "A Shorter 146Sm Half-Life Measured and Implications for 146Sm-142Nd Chronology in the Solar System". Science. 335 (6076): 1614–1617. arXiv:1109.4805. Bibcode:2012Sci...335.1614K. doi:10.1126/science.1215510. ISSN 0036-8075. PMID 22461609. S2CID 206538240.
  66. ^ Kiss, G. G.; Vitéz-Sveiczer, A.; Saito, Y.; et al. (2022). "Measuring the β-decay properties of neutron-rich exotic Pm, Sm, Eu, and Gd isotopes to constrain the nucleosynthesis yields in the rare-earth region". The Astrophysical Journal. 936 (107): 107. Bibcode:2022ApJ...936..107K. doi:10.3847/1538-4357/ac80fc. S2CID 252108123.
  67. ^ Greenwood, p. 1229
  68. ^ a b Samarium, Encyclopædia Britannica on-line
  69. ^ Delafontaine, Marc (1878). "Sur le décepium, métal nouveau de la samarskite". Journal de pharmacie et de chimie (in French). 28: 540.
  70. ^ Delafontaine, Marc (1878). "Sur le décepium, métal nouveau de la samarskite". Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 87: 632.
  71. ^ de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
  72. ^ Delafontaine, Marc (1881). "Sur le décipium et le samarium". Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 93: 63.
  73. ^ a b c Samarium: History & Etymology. Retrieved on 2013-03-21.
  74. ^ Weeks, Mary Elvira (1956). The discovery of the elements (6th ed.). Easton, PA: Journal of Chemical Education.
  75. ^ Weeks, Mary Elvira (1932). "The discovery of the elements. XIII. Some elements predicted by Mendeleeff". Journal of Chemical Education. 9 (9): 1605–1619. Bibcode:1932JChEd...9.1605W. doi:10.1021/ed009p1605.
  76. ^ Marshall, James L. Marshall; Marshall, Virginia R. Marshall (2015). "Rediscovery of the elements: The Rare Earths–The Confusing Years" (PDF). The Hexagon: 72–77. Retrieved 30 December 2019.
  77. ^ Marshall, James L. Marshall; Marshall, Virginia R. Marshall (2016). "Rediscovery of the elements: The Rare Earths–The Last Member" (PDF). The Hexagon: 4–9. Retrieved 30 December 2019.
  78. ^ Samarskite, Great Soviet Encyclopedia (in Russian)
  79. ^ Boisbaudran, Lecoq de (1879). "Recherches sur le samarium, radical d'une terre nouvelle extraite de la samarskite". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 89: 212–214.
  80. ^ Shipley, Joseph Twadell. The Origins of English Words: A Discursive Dictionary of Indo-European Roots, JHU Press, 2001, p.90. ISBN 0-8018-6784-3
  81. ^ a b "Chemistry in Its Element - Samarium". Archived from the original on 4 March 2016.
  82. ^ Coplen, T. B.; Peiser, H. S. (1998). "History of the recommended atomic-weight values from 1882 to 1997: A comparison of differences from current values to the estimated uncertainties of earlier values (Technical Report)". Pure and Applied Chemistry. 70: 237. doi:10.1351/pac199870010237. S2CID 96729044.
  83. ^ a b What are their prices?, Lynas corp.
  84. ^ a b c d e Human Health Fact Sheet on Samarium Archived 2012-04-07 at the Wayback Machine, Los Alamos National Laboratory
  85. ^ "Rare Earths" (PDF). United States Geological Surves. January 2010. Retrieved 2010-12-10.
  86. ^ Masau, M.; Cerny, P.; Cooper, M. A.; Chapman, R.; Grice, J. D. (2002-12-01). "MONAZITE-(Sm), A NEW MEMBER OF THE MONAZITE GROUP FROM THE ANNIE CLAIM #3 GRANITIC PEGMATITE, SOUTHEASTERN MANITOBA". The Canadian Mineralogist. 40 (6): 1649–1655. doi:10.2113/gscanmin.40.6.1649. ISSN 0008-4476.
  87. ^ Repina, S. A.; Popova, V. I.; Churin, E. I.; Belogub, E. V.; Khiller, V. V. (December 2011). "Florencite-(Sm)—(Sm,Nd)Al3(PO4)2(OH)6: A new mineral species of the alunite-jarosite group from the subpolar urals". Geology of Ore Deposits. 53 (7): 564–574. Bibcode:2011GeoOD..53..564R. doi:10.1134/S1075701511070191. ISSN 1075-7015. S2CID 97229772.
  88. ^ "Monazite-(Sm): Monazite-(Sm) mineral information and data". Retrieved 2016-03-04.
  89. ^ "Florencite-(Sm): Florencite-(Sm) mineral information and data". Retrieved 2016-03-04.
  90. ^ Hajra, S.; Maji, B.; Bar, S. (2007). "Samarium Triflate-Catalyzed Halogen-Promoted Friedel-Crafts Alkylation with Alkenes". Org. Lett. 9 (15): 2783–2786. doi:10.1021/ol070813t. PMID 17585769.
  91. ^ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (2007). Advanced inorganic chemistry (6th ed.). Wiley-India. p. 1128. ISBN 978-81-265-1338-3.
  92. ^ "45-year Physics Mystery Shows a Path to Quantum Transistors". Retrieved Dec 8, 2014.
  93. ^ "Centerwatch About drug Quadramet". Archived from the original on 2008-10-09. Retrieved 2009-06-06.
  94. ^ Pattison, John E. (1999). "Finger doses received during 153Sm injections". Health Physics. 77 (5): 530–5. doi:10.1097/00004032-199911000-00006. PMID 10524506.
  95. ^ Finlay, I. G.; Mason, M. D.; Shelley, M. (2005). "Radioisotopes for the palliation of metastatic bone cancer: a systematic review". The Lancet Oncology. 6 (6): 392–400. doi:10.1016/S1470-2045(05)70206-0. PMID 15925817.
  96. ^ Thermal neutron capture cross sections and resonance integrals – Fission product nuclear data.
  97. ^ DOE Fundamentals Handbook: Nuclear Physics and Reactor Theory (PDF). U.S. Department of Energy. January 1993. pp. 34, 67. Archived from the original (PDF) on March 22, 2009.
  98. ^ Bud, Robert and Gummett, Philip Cold War, Hot Science: Applied Research in Britain's Defence Laboratories, 1945–1990, NMSI Trading Ltd, 2002 ISBN 1-900747-47-2 p. 268
  99. ^ Sorokin, P. P. (1979). "Contributions of IBM to Laser Science—1960 to the Present". IBM Journal of Research and Development. 23 (5): 476. Bibcode:1979IBMJ...23..476S. doi:10.1147/rd.235.0476.
  100. ^ Zhang, J. (1997). "A Saturated X-ray Laser Beam at 7 Nanometers". Science. 276 (5315): 1097. doi:10.1126/science.276.5315.1097.
  101. ^ 20100073997, Elmegreen, Bruce G.; Krusin-elbaum, Lia & Liu, Xiao Hu et al., "Piezo-Driven Non-Volatile Memory Cell with Hysteretic Resistance", issued 2010-03-25 
  102. ^ "About us". Retrieved 2022-12-31.
  103. ^ Kaminskii, V. V.; Solov'ev, S. M.; Golubkov, A. V. (2002). "Electromotive Force Generation in Homogeneously Heated Semiconducting Samarium Monosulfide". Technical Physics Letters. 28 (3): 229. Bibcode:2002TePhL..28..229K. doi:10.1134/1.1467284. S2CID 122463906. Archived from the original on 2012-03-15.
  104. ^ Bowen, Robert and Attendorn, H -G Isotopes in the Earth Sciences, Springer, 1988, ISBN 0-412-53710-9, pp. 270 ff
  105. ^ Baur, F.; Katelnikovas, A.; Sazirnakovas, S.; Jüstel, T. (2014). "Synthesis and Optical Properties of Li3Ba2La3(MoO4)8:Sm3+". Zeitschrift für Naturforschung B. 69 (2): 183–192. doi:10.5560/ZNB.2014-3279. S2CID 197099937.
  106. ^ Riesen, Hans; Kaczmarek, Wieslaw (August 2, 2007). "Efficient X-ray Generation of Sm2+ in Nanocrystalline BaFCl/Sm3+: a Photoluminescent X-ray Storage Phosphor". Inorganic Chemistry. 46 (18): 7235–7. doi:10.1021/ic062455g. PMID 17672448.
  107. ^ Liu, Zhiqiang; Stevens-Kalceff, Marion; Riesen, Hans (March 16, 2012). "Photoluminescence and Cathodoluminescence Properties of Nanocrystalline BaFCl:Sm3+ X-ray Storage Phosphor". Journal of Physical Chemistry C. 116 (14): 8322–8331. doi:10.1021/jp301338b.
  108. ^ Wang, Xianglei; Liu, Zhiqiang; Stevens-Kalceff, Marion; Riesen, Hans (August 12, 2014). "Mechanochemical Preparation of Nanocrystalline BaFCl Doped with Samarium in the 2+ Oxidation State". Inorganic Chemistry. 53 (17): 8839–8841. doi:10.1021/ic500712b. PMID 25113662.
  109. ^ "Dosimetry&Imaging Pty Ltd". Archived from the original on 2017-09-26. Retrieved 2018-11-28.
  110. ^ Caton, Ronald G.; Pedersen, Todd R.; Groves, Keith M.; Hines, Jack; Cannon, Paul S.; Jackson-Booth, Natasha; Parris, Richard T.; Holmes, Jeffrey M.; Su, Yi-Jiun; Mishin, Evgeny V.; Roddy, Patrick A.; Viggiano, Albert A.; Shuman, Nicholas S.; Ard, Shaun G.; Bernhardt, Paul A.; Siefring, Carl L.; Retterer, John; Kudeki, Erhan; Reyes, Pablo M. (May 2017). "Artificial ionospheric modification: The Metal Oxide Space Cloud experiment" (PDF). Radio Science. 52 (5): 539–558. Bibcode:2017RaSc...52..539C. doi:10.1002/2016rs005988. S2CID 55195732.
  111. ^ Zell, Holly (7 June 2013). "First of Four Sounding Rockets Launched from the Marshall Islands". NASA.
  112. ^ "Samarium 263184". Sigma-Aldrich.