Revision as of 02:54, 18 February 2021 by imported>Double sharp
[[Category:Template:Pagetype with short description]]
Protactinium, 91Pa |
| Protactinium |
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| Pronunciation | (Template:Respell) |
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| Appearance | bright, silvery metallic luster |
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| Standard atomic weight Ar, std(Pa) | Template:Val[1] |
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| Protactinium in the periodic table |
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| Atomic number (Z) | 91 |
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| Group | group n/a |
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| Period | period 7 |
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| Block | f-block |
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| Electron configuration | [Rn] 5f2 6d1 7s2 |
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| Electrons per shell | 2, 8, 18, 32, 20, 9, 2 |
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| Physical properties |
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| Phase at STP | solid |
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| Melting point | 1841 K (1568 °C, 2854 °F) |
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| Boiling point | 4300 K (4027 °C, 7280 °F) (?) |
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| Density (near r.t.) | 15.37 g/cm3 |
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| Heat of fusion | 12.34 kJ/mol |
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| Heat of vaporization | 481 kJ/mol |
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| Atomic properties |
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| Oxidation states | +2, +3, +4, +5 (a weakly basic oxide) |
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| Electronegativity | Pauling scale: 1.5 |
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| Ionization energies | |
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| Atomic radius | empirical: 163 pm |
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| Covalent radius | 200 pm |
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| Spectral lines of protactinium |
| Other properties |
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| Natural occurrence | from decay |
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| Crystal structure | body-centered tetragonal[2] |
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| Thermal expansion | ~9.9 µm/(m·K)[3] (at r.t.) |
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| Thermal conductivity | 47 W/(m·K) |
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| Electrical resistivity | 177 nΩ·m (at 0 °C) |
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| Magnetic ordering | paramagnetic[4] |
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| CAS Number | 7440-13-3 |
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| History |
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| Prediction | Dmitri Mendeleev (1869) |
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| Discovery and first isolation | Kasimir Fajans and Oswald Helmuth Göhring (1913) |
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| Named by | Otto Hahn and Lise Meitner (1917–8) |
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| Main isotopes of protactinium |
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Category: Protactinium | references |
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References
These references will appear in the article, but this list appears only on this page.
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