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Uranium |
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Pronunciation | (yoor-AY-nee-əm) |
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Appearance | sillery gray metallic; corrodes tae a spallin black oxide coat in air |
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Standard atomic weight Ar, std(U) | 7002238028910000000♠238.02891(3)[1] |
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Uranium in the periodic cairt |
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Atomic nummer (Z) | 92 |
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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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Element category | Actinide |
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Electron confeeguration | [Rn] 5f3 6d1 7s2 |
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Electrons per shell | 2, 8, 18, 32, 21, 9, 2 |
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Pheesical properties |
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Phase at STP | solid |
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Meltin pynt | 1405.3 K (1132.2 °C, 2070 °F) |
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Bylin pynt | 4404 K (4131 °C, 7468 °F) |
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Density (near r.t.) | 19.1 g/cm3 |
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when liquid (at m.p.) | 17.3 g/cm3 |
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Heat o fusion | 9.14 kJ/mol |
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Heat o vapourisation | 417.1 kJ/mol |
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Molar heat capacity | 27.665 J/(mol·K) |
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Vapour pressur
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
2325 |
2564 |
2859 |
3234 |
3727 |
4402 |
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Atomic properties |
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Oxidation states | +1, +2, +3,[2] +4, +5, +6 waikly basic |
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Electronegativity | Pauling scale: 1.38 |
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Ionisation energies | - 1st: 597.6 kJ/mol
- 2nd: 1420 kJ/mol
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Atomic radius | empirical: 156 pm |
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Covalent radius | 196±7 pm |
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Van der Waals radius | 186 pm |
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Spectral lines o uranium |
Ither properties |
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Naitural occurrence | primordial |
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Creestal structur | orthorhombic |
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Speed o soond thin rod | 3155 m/s (at 20 °C) |
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Thermal expansion | 13.9 µm/(m·K) (at 25 °C) |
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Thermal conductivity | 27.5 W/(m·K) |
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Electrical resistivity | 0.280 µΩ·m (at 0 °C) |
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Magnetic orderin | paramagnetic |
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Young's modulus | 208 GPa |
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Shear modulus | 111 GPa |
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Bulk modulus | 100 GPa |
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Poisson ratio | 0.23 |
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Vickers haurdness | 1960–2500 MPa |
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Brinell haurdness | 2350–3850 MPa |
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CAS Nummer | 7440-61-1 |
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History |
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Namin | efter planet Uranus, itsel named efter Greek god o the sky Uranus |
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Diskivery | Martin Heinrich Klaproth (1789) |
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First isolation | Eugène-Melchior Péligot (1841) |
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Main isotopes o uranium |
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Isotope |
Abundance |
Hauf-life (t1/2) |
Decay mode |
Product |
232U |
syn |
68.9 y |
SF |
– |
α |
228Th |
233U |
trace |
1.592×105 y |
SF |
– |
α |
229Th |
234U |
0.005% |
2.455×105 y |
SF |
– |
α |
230Th |
235U |
0.720% |
7.04×108 y |
SF |
– |
α |
231Th |
236U |
trace |
2.342×107 y |
SF |
– |
α |
232Th |
238U |
99.274% |
4.468×109 y |
α |
234Th |
SF |
– |
β−β− |
238Pu |
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| references |