SAMARIUM
TRANSITION ELEMENT: LANTHANIDE
| Atomic number: | 62 |
| Group numbers: | 3 |
| Period: | 6 |
| Electronic configuration: | [Xe] 4f6 6s2 |
| Formal oxidation number: | +2 +3 |
| Electronegativities: | 1.17 |
| Atomic radius / pm: | 180.4 |
| Relative atomic mass: | 150.36(2) |
Samarium was discovered by Paul-Émile Lecoq de Boisbaudran (FR) in 1879. Named after the mineral samarskite. It is a silvery rare earth metal that is stable in dry air but reacts with water. Oxide coating forms on surfaces exposed to moist air and the metal ignites and burns readily. Samarium is found with other rare earths in monazite sand. It is used in the electronics and ceramics industries. It is easily magnetized and very difficult to demagnetise. This suggests important future applications in solid-state and superconductor technologies. The price of 99.9 % pure samarium ingot is 191.00 € for 100 g.
| Density / g dm-3: | 7520 | (293 K) |
| Molar volume / cm3mol-1: | 19.99 | (293 K) |
| Electrical resistivity / µΩcm: | 88 | (20 °C) |
| Thermal conductivity / W m-1K-1: | 13.3 |
| Melting point / °C: | 1074 |
| Boiling point / °C: | 1794 |
| Heat of fusion / kJ mol-1: | 10.9 |
| Heat of vaporization / kJ mol-1: | 164.8 |
| Heat of atomization / kJ mol-1: | 206.1 |
| First ionization energy / kJ mol-1: | 544.53 |
| Second ionization energy / kJ mol-1: | 1068.10 |
| Third ionization energy / kJ mol-1: | 2257.77 |
| in the atmosphere / ppm: | - |
| in the Earth's crust / ppm: | 3.5 |
| in the oceans / ppm: | 0.0000002 |
| Crystal structure: | rhombohedral |
| Unit-cell dimensions / pm: | a=899.6, α=23°13' |
| Space group: | R3m |
| Isotope | Relative atomic mass | Mass percent (%) |
|---|---|---|
| 144Sm | 143.911995(4) | 3.1(1) |
| 147Sm | 146.914893(3) | 15.0(2) |
| 148Sm | 147.914818(3) | 11.3(1) |
| 149Sm | 148.917180(3) | 13.8(1) |
| 150Sm | 149.917271(3) | 7.4(1) |
| 152Sm | 151.919728(3) | 26.7(2) |
| 154Sm | 153.922205(3) | 22.7(2) |
| Balanced half-reaction | Eo / V | |
|---|---|---|
| 61 Promethium | ← | 62 Samarium | → | 63 Europium |
Citing this page:
Generalic, Eni. "Samarium." EniG. Periodic Table of the Elements. KTF-Split, 18 Jan. 2024. Web. {Date of access}. <https://www.periodni.com/sm.html>.
