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|Atomic Number:||62||Atomic Symbol:||Sm|
|Atomic Weight:||150.4||Electron Configuration:||2-8-24-8-2|
|Melting Point:||1072oC||Boiling Point:||1900oC|
|Description:||Silver colored rare earth metal.|
History(Samarskite, a mineral) Discovered spectroscopically by its
sharp absorption lines in 1879 by Lecoq de Boisbaudran in the mineral
samarskite, named in honor of a Russian mine official, Col Samarski.
- Samarium is found along with other members of the rare-earth elements in
many minerals, including monazite and bastnasite, which are commercial sources.
- It occurs in monazite to the extent of 2.8%.
- While misch metal containing about 1% of samarium metal, has long been used,
samarium has not been isolated in relatively pure form until recent years.
- Ion-exchange and solvent extraction techniques have recently simplified
separation of the rare earths from one another; more rectnly, electrochemical
deposition, using an electrolytic solution of lithium citrate and a mercury
electrode, is said to be a simple, fast, and highly specific way to separate the
- Samarium metal can be produced by reducing the oxide with lanthanum.
- Samarium has a bright silver luster and is reasonably stable in air.
- Three crystal modifications of the metal exist, with transformations at 734
and 922C. The metal ignites in air at about 150C.
- Twenty one isotopes of samarium exist.
- Natural samarium is a mixture of several isotopes, three of which are
unstable with long half-lives.
- Samarium, along with other rare earths, is used for carbon-arc lighting for
the motion picture industry.
- The sulfide has excellent high-temperature stability and good thermoelectric
efficiencies up to 1100C.
- SmCo5 has been used in making a new permanent magnet material with the
highest resistance to demagnetization of any known material.
- It is said to have an intrinsic coercive force as high as 2200 kA/m.
- Samarium oxide has been used in optical glass to absorb the infrared.
- Samarium is used to dope calcium fluoride crystal for use in optical masers
- Compounds of the metal act as sensitizers for phosphors excited in the
infrared; the oxide exhibits catalytic properties in the dehydration and
dehydrogenation of ethyl alcohol.
- It is used in infrared absorbing glass and as a neutron absorber in nuclear
CostsThe metal is priced at about $5/g.