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 :
~>SAMARIUM is a chemical element with symbol Sm and atomic number 62. It is a moderately hard silvery metal that readily oxidizes in air. Being a typical member of the lanthanide series, samarium usually assumes the oxidation state +3.
| FACT BOX | |||
| 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 | |
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.