| Discovery date | 1879 |
| Discovered by | Paul-Émile Lecoq de Boisbaudran |
| Origin of the name | The name is derived from samarskite, the name of the mineral from which it was first isolated. |
| Allotropes |
|
Sm
Samarium
62
150.36
| Group | Lanthanides | Melting point | 1072°C, 1962°F, 1345 K |
| Period | 6 | Boiling point | 1794°C, 3261°F, 2067 K |
| Block | f | Density (g cm−3) | 7.52 |
| Atomic number | 62 | Relative atomic mass | 150.36 |
| State at 20°C | Solid | Key isotopes | 152Sm |
| Electron configuration | [Xe] 4f66s2 | CAS number | 7440-19-9 |
| ChemSpider ID | 22391 | ChemSpider is a free chemical structure database | |
Image explanation
The mineral samarskite, from which samarium was first isolated, is named after Colonel Samarsky, a Russian mine official. The Soviet hammer, sickle and star are on a background that reflects the use of the element in lasers.
Appearance
A silvery-white metal.
Uses
Samarium-cobalt magnets are much more powerful than iron magnets. They remain magnetic at high temperatures and so are used in microwave applications. They enabled the miniaturisation of electronic devices like headphones, and the development of personal stereos. However, neodymium magnets are now more commonly used instead.
Samarium is used to dope calcium chloride crystals for use in optical lasers. It is also used in infrared absorbing glass and as a neutron absorber in nuclear reactors. Samarium oxide finds specialised use in glass and ceramics. In common with other lanthanides, samarium is used in carbon arc lighting for studio lighting and projection.
Biological role
Samarium has no known biological role. It has low toxicity.
Natural abundance
Samarium is found along with other lanthanide metals in several minerals, the principal ones being monazite and bastnaesite. It is separated from the other components of the mineral by ion exchange and solvent extraction.
Recently, electrochemical deposition has been used to separate samarium from other lanthanides. A lithium citrate electrolyte is used, and a mercury electrode. Samarium metal can also be produced by reducing the oxide with barium.
Samarium was one of the rare earths (aka lanthanoids) which perplexed and puzzled the chemists of the 1800s. Its history began with the discovery of cerium in 1803. This was suspected of harbouring other metals, and in 1839 Carl Mosander claimed to have obtained lanthanum and didymium from it. While he was right about lanthanum, he was wrong about didymium. In 1879, Paul-Émile Lecoq de Boisbaudran extracted didymium from the mineral samarskite. He then made a solution of didymium nitrate and added ammonium hydroxide. He observed that the precipitate which formed came down in two stages. He concentrated his attention on the first precipitate and measured its spectrum which revealed it to be a new element samarium. Samarium itself was eventually to yield other rare-earths: gadolinium in 1886 and europium in 1901.
| Atomic radius, non-bonded (Å) | 2.36 | Covalent radius (Å) | 1.85 |
| Electron affinity (kJ mol−1) | Unknown |
Electronegativity (Pauling scale) |
1.17 |
|
Ionisation energies (kJ mol−1) |
1st
544.534
2nd
1068.09
3rd
2257.8
4th
3994.5
5th
-
6th
-
7th
-
8th
-
|
||
| Common oxidation states | 3, 2 | ||||
| Isotopes | Isotope | Atomic mass | Natural abundance (%) | Half life | Mode of decay |
| 144Sm | 143.912 | 3.07 | - | - | |
| 147Sm | 146.915 | 14.99 | 1.06 x 1011 y | a | |
| 148Sm | 147.915 | 11.24 | 7 x 1015 y | a | |
| 149Sm | 148.917 | 13.82 | 1016 y | a | |
| 150Sm | 149.917 | 7.38 | - | - | |
| 152Sm | 151.920 | 26.75 | - | - | |
| 154Sm | 153.922 | 22.75 | - | - | |
|
|
|
Specific heat capacity (J kg−1 K−1) |
196 | Young's modulus (GPa) | 49.7 | |||||||||||
| Shear modulus (GPa) | 19.5 | Bulk modulus (GPa) | 37.8 | |||||||||||
| Vapour pressure | ||||||||||||||
| Temperature (K) |
|
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| Pressure (Pa) |
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| Listen to Samarium Podcast |
|
Transcript :
Chemistry in its element: samarium(Promo) You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry. (End promo) Meera Senthilingam This week, a rare, lustrous element with isotopes that have some unfathomably long half-lives. To tell us more, here's Richard Corfield: Richard Corfield Samarium is a rare earth element that - indirectly - has the distinction of being the first naturally occurring chemical element to be named after a living person. Samarium was isolated from the mineral Samarskite which was discovered near the small town of Miass in the southern Ural mountains in 1847. The mineral was named by the German Mineralogist Heinrich Rose after Vasili Evgrafovich Samarsky-Bykhovets, Chief of Staff of the Russian Corps of Mining Engineers between 1845 and 1861 who had given Rose the ore sample to study. Meera Senthilingham So get those samarium shares in ASAP. That was science writer Richard Corfield with the geological and technological uses of the element samarium. Now next week, we stick with the lanthanides and hear about an element that likes to play hard to get. Simon Cotton At that time, scientists were using improved techniques such as fractional crystallisation to obtain the individual lanthanides from mixtures. In 1886, Lecoq was the first person to identify dysprosium by separating its oxide from holmium oxide. It took him over 30 goes to do this, so he named the element accordingly, from the Greek word, dysprositos, meaning "hard to get at". Meera Senthilingham And Simon Cotton will be sharing some of the chemistry, properties and applications of dysprosium in next week's Chemistry in its Element. Until then, I'm Meera Senthilingham and thank you for listening (Promo) Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com. There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements. (End promo) |
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Visual Elements images and videos
© Murray Robertson 1998-2017.
W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.
John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.
Derived in part from material provided by the British Geological Survey © NERC.
Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.
Produced by The Naked Scientists.
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
© Murray Robertson 1998-2017.
Data
W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.
Uses and properties
John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.
Supply risk data
Derived in part from material provided by the British Geological Survey © NERC.
History text
Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.
Podcasts
Produced by The Naked Scientists.
Periodic Table of Videos
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
