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Samarium ( after the mineral Samarskite, which was appointed by the German mineralogist Heinrich Rose after the Russian mining engineer Vasily M. Samarski ) is a chemical element with the element symbol Sm and atomic number 62 in the periodic table the polished silver element is in the group of lanthanides and also makes it one of the metals of the rare earths. Samarium is the first naturally occurring element that was named after a person.


To the discovery of samarium exist in the literature, several representations.

In 1903, the German chemist Wilhelm Muthmann metallic samarium ago by electrolysis.


Solidity comes elemental samarium not before. However, some minerals such as monazite, Bastnäsit and Samarskite contain the element. Monazite comprises up to 1% of samarium.

Production and representation

Starting from monazite or Bastnäsit rare earths by ion exchange, solvent extraction and electrochemical deposition are separated. In a last step, the high purity samarium oxide is reduced to metallic lanthanum to the metal and sublimed.


In air, samarium is reasonably stable, it forms a passivating oxide layer of yellowish. Shiny metallic samarium ignites above 150 ° C. With oxygen it reacts to the sesquioxide Sm2O3. With water it reacts violently to produce hydrogen and Samariumhydroxid. The most stable oxidation state, as with all lanthanides 3. Samarium occurs in three modifications. The transition points are at 734 ° C and 922 ° C. Sm3 cations color yellow aqueous solutions.


There are four stable and 19 unstable, radioactive isotopes. The most frequent natural isotopes 152Sm (26.7%), 154Sm (22.7%) and 147Sm (15 %).


  • Along with other rare earths for carbon arc lamps for Filmvorführanlagen.
  • Doping of calcium fluoride single crystals for laser and maser.
  • Because of its large cross section for thermal and epithermal neutrons Samarium is used as a neutron absorber in nuclear applications. Sm -149 is produced as well as the cleavage product, it is an inevitable neutron poison in nuclear reactors.
  • Samarium- cobalt magnets: SmCo5 permanent magnets have a high resistance to demagnetization and a coercivity of 2200 kA / m. The improved alloy Sm2Co17 is expensive to manufacture, but has higher magnetic properties and improved corrosion resistance. They are used in step motors for quartz watches, drive motors in micro tape recorders ( Walkman, dictation ), headphones, sensors, clutches in mixers and hard disk drives. As a weight-saving magnetic materials are also used in the aerospace industry.
  • Samarium oxide is added to optical glass to absorb infrared light.
  • Samarium one uses to raise awareness of (light - ) phosphorus when irradiated with infrared light.
  • As a catalyst; Samarium oxide catalyzes the hydrogenation and dehydrogenation of ethanol ( alcohol).
  • In the medical isotope 153Samarium is used in conjunction with a bisphosphonate ( Lexidronam ) for the treatment of bone cancer pain ( radionuclide therapy of bone metastases ).
  • Compounds of samarium in the 2 oxidation state less favorable (in particular samarium ( II) iodide, and samarium ( II) bromide ) are used in the organic synthesis (reducing agent and an electron Transferreagenz, e.g. pinacol samariumvermittelte couplings).
  • In conjunction with the radiopharmaceutical ethylene diamine tetra ( methylene phosphonic acid) in nuclear medicine for palliative therapy of bone and skeletal metastases.


  • Samarium (III ) oxide, Sm2O3
  • Samarium (III ) fluoride SmF3
  • Samarium ( III) chloride SmCl3
  • Samarium ( II) bromide SmBr2
  • Samarium (III ) bromide SmBr3
  • Samarium ( II) iodide SmI2
  • Samarium (III ) iodide SmI3
  • Samarium (III ) sulphate Sm2 (SO4) 3
  • Samarium- cobalt Sm2Co7
  • Samarium- 153- EDTMP