| Symbol | Sm |
| Atomic number | 62 |
| Group | - |
| Period | 6 |
| Block | f |
| Classification | Lanthanide |
| Appearance | Silvery white |
| Color | Silver |
| Number of protons | 62 p+ |
| Number of neutrons | 88 n0 |
| Number of electrons | 62 e- |
| Phase at STP | Solid |
| Density | 7.52 g/cm3 |
| Atomic weight | 150.362 u |
| Melting point | 1345 K 1071.85 °C 1961.33 °F |
| Boiling point | 2173 K 1899.85 °C 3451.73 °F |
| Heat of vaporization | 191.63 kJ/mol |
| Electronegativity (Pauling Scale) | 1.17 |
| Electron affinity | 15.63 kJ/mol |
| Oxidation states | 0, +2, +3 (a mildly basic oxide) |
| Ionization energies |
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| Discovery and first isolation | Lecoq de Boisbaudran (1879) |
| Named by | Lecoq de Boisbaudran |
Discovery of samarium Detection of samarium and related elements was announced by several scientists in the second half of the 19th century; however, most sources give priority to French chemist Paul-Émile Lecoq de Boisbaudran. Boisbaudran isolated samarium oxide and/or hydroxide in Paris in 1879 from the mineral samarskite and identified a new element in it via sharp optical absorption lines. Swiss chemist Marc Delafontaine announced a new element decipium (from Latin: decipiens meaning "deceptive, misleading") in 1878, but later in 1880–1881 demonstrated that it was a mix of several elements, one being identical to Boisbaudran's samarium. Though samarskite was first found in the remote Russian region of Urals, by the late 1870s it had been found in other places, making it available to many researchers. In particular, it was found that the samarium isolated by Boisbaudran was also impure and had a comparable amount of europium. The pure element was produced only in 1901 by Eugène-Anatole Demarçay. Boisbaudran named his element samaria after the mineral samarskite, which in turn honored Vassili Samarsky-Bykhovets (1803–1870). | |