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Samarium (Sm)

Samarium is a chemical element of the periodic table with chemical symbol Sm and atomic number 62 with an atomic weight of 150.362 u and is classed as lanthanide. Samarium is solid at room temperature.

Samarium in the periodic table

Atomic number62
AppearanceSilvery white
Color Silver
Number of protons62 p+
Number of neutrons88 n0
Number of electrons62 e-
From Wikipedia, the free encyclopediaSamarium 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.

Physical properties

Phase at STPSolid
Density7.52 g/cm3
Atomic weight150.362 u

Thermal properties

Melting point1345 K
1071.85 °C
1961.33 °F
Boiling point2173 K
1899.85 °C
3451.73 °F
Heat of vaporization191.63 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.17
Electron affinity15.63 kJ/mol
Oxidation states0, +2, +3
(a mildly basic oxide)
Ionization energies
  1. 544.5 kJ/mol
  2. 1070 kJ/mol
  3. 2260 kJ/mol
  4. 3990 kJ/mol

Electron configuration for samarium

Electron configuration
Shorthand configuration
[Xe] 4f6 6s2
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f6 5s2 5p6 6s2
Electron configuration chart
Electrons per shell2, 8, 18, 24, 8, 2
Valence electrons 2
Valency electrons 3
Bohr model
SamariumElectron shell for Samarium, created by Injosoft ABSm
Figure: Shell diagram of Samarium (Sm) atom.
Orbital Diagram

The history of Samarium

Discovery and first isolationLecoq de Boisbaudran (1879)
Named byLecoq 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).


List of unique identifiers for Samarium in various chemical registry databases
CAS Number7440-19-9
ChemSpider ID22391
EC number231-128-7
PubChem CID Number23951