The mineralogy of Promethium
| General Properties | |
|---|---|
| Symbol: | Pm |
| Other names: | Promethium is a lanthanide element with no stable isotopes, indeed its longest-living isotope (145) has a half-life of less than 18 years. As such any primordial promethium has long since decayed, and the only promethium to be found naturally in the Earth is tiny amounts refreshed from the decay of uranium. There are probably less than 600 grams of promethium in the Earth's crust at any moment. |
| Atomic Number: | 61 |
| Standard atomic weight (Ar): | [145] |
| Electron configuration: | [Xe] 4f5 6s2 |
| Photos | ||
|---|---|---|
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| < | Promethium(III) chloride being used as part of a luminous paint mixture. | > |
| Atomic Properties | |
|---|---|
| Electronegativity (Pauling scale): | 1.13 |
| Atomic Radius: | 205 pm |
| Ionic Radius: | 97 pm (+3) |
| 1st Ionization energy: | 540 kJ/mol |
| 1st Electron affinity: | -50 kJ/mol |
| Oxidation States: | 3 |
| Physical Properties | |
|---|---|
| Standard State: | solid |
| Bonding Type: | metallic |
| Melting Point: | 1373 K |
| Boiling Point: | 3273 K |
| Density: | 7.26 g/cm3 |
| Metal/Non-Metal: | lanthanoid |
| Main isotopes of Promethium | ||||
|---|---|---|---|---|
| Isotope | % in Nature | Half Life | Decay type | Decay product |
| 145Pm | synthetic | 17.7y | ε | 145Nd |
| 146Pm | synthetic | 5.53y | ε | 146Nd |
| β− | 146Sm | |||
| 147Pm | trace | 2.6234y | β− | 147Sm |
| Main ions of Promethium | ||||
|---|---|---|---|---|
| Name | Ion | Example minerals | ||
| promethium(III) | Pm3+ | |||
| Other Information | |
|---|---|
| Year Discovered: | 1942 |
| Discovered By: |  Chien shiung Wu  Emilio Segrè  Hans Albrecht Bethe Chien Shiung Wu, Emilio Segrè, Hans Bethe |
| Year Isolated: | 1945 |
| Isolated By: |  Charles D. Coryell  Jacob Akiba Marinsky  Lawrence Elgin Glendenin Charles D. Coryell, Jacob A. Marinsky, Lawrence E. Glendenin, Harold G. Richter |
| Named For: |  Prometheus |
| CPK color coding: | #A3FFC7 |
| External Links: | WikipediaWebElementsLos Alamos National LaboratoryTheodore Gray's PeriodicTable.com |