Samarium
LANTHANOID · GROUP None · PERIOD 6
62
Sm
Samarium
150.36
Atomic Data
| Atomic Number | 62 |
| Symbol | Sm |
| Atomic Weight | 150.36 u |
| Density (STP) | 7.52 g/cm³ |
| Melting Point | 1071.85 °C (1345 K) |
| Boiling Point | 1793.85 °C (2067 K) |
| Electronegativity | 1.17 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f6 5s2 5p6 6s2 |
| Oxidation States | +2, +3 |
| Phase at STP | Solid |
| Category | Lanthanoid |
| Period / Group | 6 / None |
| CAS Number | 7440-19-9 |
Electron Configuration
{{BOHR_SVG}}
[Xe] 4f6 6s2
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 10 | 28 |
| N | 4 | 4s | 2 | 30 |
| N | 4 | 4p | 6 | 36 |
| N | 4 | 4d | 10 | 46 |
| N | 4 | 4f | 6 | 52 |
| O | 5 | 5s | 2 | 54 |
| O | 5 | 5p | 6 | 60 |
| P | 6 | 6s | 2 | 62 |
| Total | 62 | 62 | ||
Isotopes of Samarium
Samarium has seven naturally occurring stable isotopes. The most abundant is ¹⁵²Sm, comprising 26.75% of all naturally occurring Samarium.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Samarium-144 | ¹⁴⁴Sm | 62 | 82 | 3.08 | Stable |
| Samarium-147 | ¹⁴⁷Sm | 62 | 85 | 14.99 | Stable |
| Samarium-148 | ¹⁴⁸Sm | 62 | 86 | 11.24 | Stable |
| Samarium-149 | ¹⁴⁹Sm | 62 | 87 | 13.82 | Stable |
| Samarium-150 | ¹⁵⁰Sm | 62 | 88 | 7.38 | Stable |
| Samarium-152 | ¹⁵²Sm | 62 | 90 | 26.75 | Stable |
| Samarium-154 | ¹⁵⁴Sm | 62 | 92 | 22.74 | Stable |
Abundance & Occurrence
Samarium is present in Earth's crust at approximately 7.9 ppm by mass and at approximately 0.5 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Samarium
7.9 ppm
Silicon (ref.)
277,000 ppm
Oxygen (ref.)
461,000 ppm
Universe (ppm by mass)
Samarium
0.5 ppm
Helium (ref.)
230,000 ppm
Hydrogen (ref.)
739,000 ppm
Discovery & History
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Safety & Handling
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Samarium in the Real World
Real-World Uses
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Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.