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Neptunium, 93NpFile:NonFreeImageRemoved.svg |
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Pronunciation | (nep-TEW-nee-əm) |
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Appearance | silvery metallic |
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Mass number | [237] |
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Atomic number (Z) | 93 |
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Group | f-block groups (no number) |
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Period | period 7 |
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Block | f-block |
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Electron configuration | [Rn] 5f4 6d1 7s2 |
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Electrons per shell | 2, 8, 18, 32, 22, 9, 2 |
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Phase at STP | solid |
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Melting point | 912±3 K (639±3 °C, 1182±5 °F) |
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Boiling point | 4447 K (4174 °C, 7545 °F) (extrapolated) |
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Density (at 20° C) | 20.48 g/cm3 (237Np)[1] |
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Heat of fusion | 5.19 kJ/mol |
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Heat of vaporization | 336 kJ/mol |
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Molar heat capacity | 29.46 J/(mol·K) |
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Vapor pressure
P (Pa)
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1
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10
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100
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1 k
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10 k
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100 k
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at T (K)
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2194
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2437
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Oxidation states | common: +5
+2,? +3,[2] +4,[3] +6,[2] +7[2] |
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Electronegativity | Pauling scale: 1.36 |
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Ionization energies | |
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Atomic radius | empirical: 155 pm |
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Covalent radius | 190±1 pm |
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Color lines in a spectral rangeSpectral lines of neptunium |
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Natural occurrence | from decay |
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Crystal structure | orthorhombic (oP8) |
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Lattice constants | a = 472.3 pm b = 488.7 pm c = 666.3 pm (at 20 °C)[1] |
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Thermal conductivity | 6.3 W/(m⋅K) |
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Electrical resistivity | 1.220 µΩ⋅m (at 22 °C) |
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Magnetic ordering | paramagnetic[4] |
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CAS Number | 7439-99-8 |
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Naming | after planet Neptune, itself named after Roman god of the sea Neptune |
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Discovery | Edwin McMillan and Philip H. Abelson (1940) |
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File:Symbol category class.svg Category: Neptunium | references |
child table, as reused in {IB-Np} |
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References
These references will appear in the article, but this list appears only on this page.
- ↑ Jump up to: 1.0 1.1 Lua error in Module:Citation/CS1/Configuration at line 2088: attempt to index field '?' (a nil value).
- ↑ Jump up to: 2.0 2.1 2.2 Lua error in Module:Citation/CS1/Configuration at line 2088: attempt to index field '?' (a nil value).
- ↑ Np(II), (III) and (IV) have been observed, see Lua error in Module:Citation/CS1/Configuration at line 2088: attempt to index field '?' (a nil value).
- ↑ Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.
- ↑ Jump up to: 5.0 5.1 Lua error in Module:Citation/CS1/Configuration at line 2088: attempt to index field '?' (a nil value).
Lua error in mw.title.lua at line 230: too many expensive function calls.