Samarium (Sm)
Samarium is element 62, a lanthanide in period 6 of the periodic table. At room temperature it is a solid.
Electron configuration [Xe] 4f6 6s2
Electrons per shell 2, 8, 18, 24, 8, 2
Samarium data
| Atomic number | 62 |
|---|---|
| Symbol | Sm |
| Atomic mass | 150.36 u |
| Category | Lanthanide |
| Group | — (f-block) |
| Period | 6 |
| Block | f |
| State at 25 °C | solid |
| Melting point | 1345 K (1071.9 °C) |
| Boiling point | 2076 K (1802.9 °C) |
| Density | 7.353 g/cm³ |
| Electronegativity (Pauling) | 1.17 |
| Atomic radius | — |
| 1st ionization energy | 545 kJ/mol |
| Electron affinity | -50 kJ/mol |
| Oxidation states | +2, +3 |
| Common ion charge | 3+, 2+ |
| Discovered | 1853 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through samarium’s configuration and its ions →
Where samarium sits
Samarium belongs to the lanthanides. Its Pauling electronegativity of 1.17 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Samarium FAQ
What is the electron configuration of samarium?
Samarium (Z = 62) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f6 6s2. In noble-gas shorthand that is [Xe] 4f6 6s2.
How many valence electrons does samarium have?
2 (2 in the outer s subshell).
What is the atomic mass of samarium?
The standard atomic weight of samarium is 150.36 u, so one mole weighs 150.36 g.
Is samarium a metal?
Yes. Samarium is a lanthanide.
What is the charge of a samarium ion?
Samarium most commonly forms Sm3+ or Sm2+.