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Pronunciation | (ploo-TOH-nee-əm) |
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Allotropes | see Allotropes of plutonium |
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Appearance | silvery white, tarnishing to dark gray in air |
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Mass number | [244] |
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Atomic number (Z) | 94 |
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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] 5f6 7s2 |
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Electrons per shell | 2, 8, 18, 32, 24, 8, 2 |
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Phase at STP | solid |
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Melting point | 912.5 K (639.4 °C, 1182.9 °F) |
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Boiling point | 3505 K (3228 °C, 5842 °F) |
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Density (near r.t.) | 19.85 g/cm3 (239Pu)[1] |
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when liquid (at m.p.) | 16.63 g/cm3 |
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Heat of fusion | 2.82 kJ/mol |
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Heat of vaporization | 333.5 kJ/mol |
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Molar heat capacity | 35.5 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
1756 |
1953 |
2198 |
2511 |
2926 |
3499 |
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Oxidation states | +2, +3, +4, +5, +6, +7, +8 (an amphoteric oxide) |
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Electronegativity | Pauling scale: 1.28 |
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Ionization energies | |
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Atomic radius | empirical: 159 pm |
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Covalent radius | 187±1 pm |
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Spectral lines of plutonium |
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Natural occurrence | from decay |
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Crystal structure | monoclinic |
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Speed of sound | 2260 m/s |
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Thermal expansion | 46.7 µm/(m⋅K) (at 25 °C) |
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Thermal conductivity | 6.74 W/(m⋅K) |
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Electrical resistivity | 1.460 µΩ⋅m (at 0 °C) |
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Magnetic ordering | paramagnetic |
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Young's modulus | 96 GPa |
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Shear modulus | 43 GPa |
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Poisson ratio | 0.21 |
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CAS Number | 7440-07-5 |
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Naming | after dwarf planet Pluto, itself named after classical god of the underworld Pluto |
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Discovery | Glenn T. Seaborg, Arthur Wahl, Joseph W. Kennedy, Edwin McMillan (1940–1941) |
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Main isotopes[2] |
Decay |
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abundance |
half-life (t1/2) |
mode |
product |
238Pu |
trace |
87.7 y |
α |
234U |
SF |
– |
239Pu |
trace |
2.411×104 y |
α |
235U |
SF |
– |
240Pu |
trace |
6.561×103 y |
α |
236U |
SF |
– |
241Pu |
synth |
14.329 y |
β− |
241Am |
α |
237U |
SF |
– |
242Pu |
synth |
3.75×105 y |
α |
238U |
SF |
– |
244Pu |
trace |
81.3×106 y |
α |
240U |
SF |
– |
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Category: Plutonium | references |