Samarium
lanthanide · period 6 · group 3 · f-block
Samarium is a chemical element with the symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air.
What the numbers say
At standard temperature and pressure Samarium is a solid, sitting in period 6, group 3 of the f-block.
Its melting point of 1345 K (1072 °C) is the 45th highest of the 110 elements with a measured value — mid-range among the elements.
At 7.353 g/cm³ it is the 44th densest of 96 elements with a quoted density.
Pauling electronegativity is 1.17. Paired with oxygen (3.44) that is a difference of 2.27, which puts the bond predominantly ionic — expect a stable oxide ceramic.
In the solid state it takes a simple trigonal structure.
It is reported in 2 oxidation states (2, 3), which sets how many distinct compounds and phases it can form.
First identified in 1879.
Crystal structure
Solid Samarium adopts a Simple Trigonal arrangement, in the Trigonal (rhombohedral) system — axes a = b = c (rhombohedral setting), angles α = β = γ ≠ 90°. Symmetry controls the anisotropy of stiffness and thermal expansion, and the available slip systems set how far the metal deforms before it fractures.
Check it against computed structures
The structure search queries the Materials Project, OQMD and the Open Materials Database for computed crystal structures containing Sm — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 8 · M 18 · N 24 · O 8 · P 2
Properties
| Atomic number | 62 |
|---|---|
| Atomic mass | 150.362 u |
| Series | lanthanide |
| Group | 3 |
| Period | 6 |
| Block | f-block |
| Phase at STP | Solid |
| Density | 7.353 g/cm³ |
| Melting point | 1345 K (1072 °C) |
| Boiling point | 2173 K (1900 °C) |
| Electronegativity (Pauling) | 1.17 |
| Electron configuration | [Xe] 4f⁶ 6s² |
| Crystal structure | Simple Trigonal |
| Oxidation states | 2,3 |
| Discovered | 1879 |
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See Sm in context with all 118 elements.
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