Pu
Plutonium
PLUTONIUM
TRANSITION ELEMENT: ACTINIDE
| Atomic number: | 94 |
| Group numbers: | 3 |
| Period: | 7 |
| Electronic configuration: | [Rn] 5f6 7s2 |
| Formal oxidation number: | +3 +4 +5 +6 |
| Electronegativities: | 1.3 |
| Atomic radius / pm: | 151.3 |
| Relative atomic mass: | - |
Plutonium was discovered by Glenn Theodore Seaborg, Joseph W. Kennedy, and Arthur C. Wahl (US) in 1940. Named after the planet Pluto. It is a silvery-white, extremely radioactive, highly toxic, artificially produced metal that reacts with oxygen, acids and steam, but it resists alkalis. Plutonium is rarely found in uranium ores. It can be made by bombarding uranium with neutrons. Plutonium was used in bombs and reactors. Small quantities are used in thermo-electric generators.
| Density / g dm-3: | 19840 | (298 K) |
| 16623 | (m.p.) | |
| Molar volume / cm3mol-1: | 12.30 | (298 K) |
| 14.68 | (m.p.) | |
| Electrical resistivity / µΩcm: | 150 | (20 °C) |
| Thermal conductivity / W m-1K-1: | 6.74 |
| Melting point / °C: | 640 |
| Boiling point / °C: | 3228 |
| Heat of fusion / kJ mol-1: | 2.8 |
| Heat of vaporization / kJ mol-1: | 343.5 |
| Heat of atomization / kJ mol-1: | 348 |
| First ionization energy / kJ mol-1: | 581.44 |
| Second ionization energy / kJ mol-1: | - |
| Third ionization energy / kJ mol-1: | - |
| in the atmosphere / ppm: | - |
| in the Earth's crust / ppm: | - |
| in the oceans / ppm: | - |
| Crystal structure: | simple monoclinic |
| Unit-cell dimensions / pm: | a=618.3, b=482.2, c=1096.3, β=101.79° |
| Space group: | P21m |
| Isotope | Relative atomic mass | Mass percent (%) |
|---|---|---|
| 238Pu | 238.049 56(2) | * |
| 239Pu | 239.052 16(2) | * |
| 240Pu | 240.053 81(2) | * |
| 241Pu | 241.056 85(2) | * |
| 242Pu | 242.058 74(2) | * |
| 244Pu | 244.064 21(4) | * |
| Balanced half-reaction | Eo / V | |
|---|---|---|
| Pu4+ + e- → Pu3+ | +0.970 | |
| Pu3+ + 3e- → Pu(s) | - 2.03 | |
| PuO22+ + 4H+ + 2e- → Pu4+ + 2H2O | +1.04 | |
| PuO22+ + e- → PuO2+ | +0.916 | |
| Pu(OH)3(s) + 3e- → Pu(s) + 3OH- | - 2.42 | |
| Pu(OH)4(s) + e- → Pu(OH)3(s) + OH- | - 0.95 |
| 93 Neptunium | ← | 94 Plutonium | → | 95 Americium |
Citing this page:
Generalic, Eni. "Plutonium." EniG. Periodic Table of the Elements. KTF-Split, 18 Jan. 2024. Web. {Date of access}. <https://www.periodni.com/pu.html>.
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