Promethium
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| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Promethium, Pm | ||||
| Pronunciation |
/proʊˈmiːθiəm/ (proh-MEE-thee-əm) | ||||
| Appearance | Metallic | ||||
| Promethium in the periodic table | |||||
| |||||
| Atomic number | 61 | ||||
| Standard atomic weight (Ar) | |||||
| Group, block | n/a; f-block | ||||
| Period | period 6 | ||||
| Electron configuration | [Xe] 4f5 6s2 | ||||
per shell | 2, 8, 18, 23, 8, 2 | ||||
| Physical properties | |||||
| Phase | Solid | ||||
| Melting point | 1315 K (1042 °C, 1908 °F) | ||||
| Boiling point | 3273 K (3000 °C, 5432 °F) | ||||
| Density near r.t. | 7.26 g/cm3 | ||||
| Heat of fusion | 7.13 kJ/mol | ||||
| Heat of | 289 kJ/mol | ||||
| Atomic properties | |||||
| Oxidation states | +2, +3 | ||||
| energies |
1st: 540 kJ/mol 2nd: 1050 kJ/mol 3rd: 2150 kJ/mol | ||||
| Atomic radius | empirical: 183 pm | ||||
| Covalent radius | 199 pm | ||||
| Miscellanea | |||||
| Crystal structure | | ||||
| Thermal expansion | 9.0 µm/(m·K) (at room temperature) | ||||
| Thermal conductivity | 17.9 W/(m·K) | ||||
| Electrical resistivity | 0.75 Ω·m (at 20 °C) (estimated) | ||||
| Magnetic ordering | paramagnetic | ||||
| Young's modulus | α form: est. 46 GPa | ||||
| Shear modulus | α form: est. 18 GPa | ||||
| Bulk modulus | α form: est. 33 GPa | ||||
| Poisson ratio | α form: est. 0.28 GPa | ||||
| CAS Registry Number | 7440-12-2 | ||||
| History | |||||
| Discovery | Chien Shiung Wu, Emilio Segrè, Hans Bethe (1942) | ||||
| First isolation | Charles D. Coryell, Jacob A. Marinsky, Lawrence E. Glendenin (1945) | ||||
| Named by | Grace Mary Coryell (1945) | ||||
Promethium is an extremely radioactive lanthanide. It is one of two classical elements lighter than bismuth, with no stable isotopes, the other being technetium. It is not encountered in nature except for traces and is primarily synthesized in labs.
Contents
Properties
Chemical
The chemistry of promethium is very similar to that of other lanthanides.
Physical
Promethium is a silvery-gray metal, which glows in dark. It readily oxidizes in air.
Availability
Promethium is extremely hard to find, but some sellers do exist. It's very expensive.
Isolation
To do
Projects
- Element collection
- Study radioactivity
- Luminous paint
- Atomic batteries
Handling
Safety
Promethium is highly radioactive and proper protection should be worn when handling the compound.
Storage
In closed vials, kept in lead-lined boxes.
Disposal
To do
