Samarium (Sm)

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Samarium 62Sm150.36

Discovered in 1879 by P.-E. Lecoq de Boisbaudran at Paris, France.

[Named after the mineral samarskit]

French: samarium
German: Samarium
Italian: samario
Spanish: samario

Description: Samarium is a silvery-white metal of the so-called rare earth group (more correctly termed the lanthanoides). It is relatively stable in dry air, but in moist air an oxide coating forms. Samarium is used in permanent magnets, organic reagents, special glass, catalysts, cermics and elctronics.


Further Materials properties


Crystal structure:

(cell dimensions/pm), space group, 
α-Sa rhombohedral (a=899.6, α=23° 13'), R-3m
β-Sa cubic (a=407), Im3m
T (α -> β) = 1190 K
high pressure form: h.c.p. (a=361.8, c=1 166), P63/mmc

X-ray diffractions mass absorption coefficients: CuKa 397 (µ/r) / cm2g-1
MoKa 58.6 (µ/r) / cm2g-1
Neutron scattering length: 0.080 b/10-12 cm
Thermal neutron capture cross-section: 5922 sa / barns
Density: 7520 kg/m-3 [293 K]
Melting point: 1076.85°C / 1350°K
Boiling point: 1790.85°C / 2064°K
Molar volume: 20.00 cm3
Thermal conductivity: 13.3 [300 K] W m-1K-1
Coefficient of linear thermal expansion: 10.4 x 10-6 K-1
Electrical resistivity: 94.0 x 10-8 [298 K] Ωm
Mass magnetic susceptibility: +1.52 x 10-7(s) kg-1m3
Radi: Sm3+ 100Sm2+ 111; atomic 180; covalent 166
Electronegativity: 1.17 (Pauling); 1.07 (Allred); ≤ 3.1 eV (absolute)
Effective nuclear charge: 2.85 (Slater); 8.01 (Clementi); 11.06 (Froese-Fischer)
Number of Isotopes (incl. nuclear isomers): 24
Isotope mass range: 138-> 158



Biological data


Biological role: None, but acts to stimulate metabolism.
Toxic intake: n.a.
Lethal intake: LD50 (nitrate, oral, rat) = 2900 mg Kg-1
Hazards: Samarium is mildly toxic by ingestion, and is a skin and eye iritant.
Level in humans
Blood: 0.008 mg dm-3
Organs: n.a., but very low
Daily dietary intake: n.a. 
Total mass of element in average
[70 kg] person:
c. 0.05 mg


Geological data


MineralFormulaDensityHardnessCrystal apperance
Monazite-La  (La, Ce, Nd, Th, etc.)PO4 5.20  5 - 5.5  mon., waxy/vit. yellow-brown

* Although not a major constituent, samarium is present in extractable amounts.

Chief ores: monazite
World production: c. 700 tonnes/year
Producing areas: USA, Brazil, India, Sri Lanka, Australia
Reserves: c. 2 x 106 tonnes
Specimen: available as chips or ingots. Safe.


Sun: 5.2 (relative to H = 1 x 1012)
Earth's crust: 7.9 ppm
Atlantic surface: 4.0 x 10-7 ppm
Atlantic deep: 6.4 x 10-7 ppm
Pacific surface: 4.0 x 10-7 ppm
Pacific deep: 10 x 10-7 ppm
Residence time: 200 years
Classification: recycled
Oxidation state: III

  Source: Emsley, J. (1998) The Elements (3rd Edition)

Other sizes and specifications on request

Overview of elements with access to our shop

1 18
2 13 14 15 16 17
Li Be B C
Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se
Rb Sr Y Zr Nb Mo
Ru Rh Pd Ag Cd In Sn Sb Te I
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi
Ce Pr Nd
Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

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