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Pronunciation | (yuu-ROH-pee-əm) |
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Appearance | silvery white, with a pale yellow tint;[1] but rarely seen without oxide discoloration |
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| 151.964(1)[2] |
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Atomic number (Z) | 63 |
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Group | f-block groups (no number) |
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Period | period 6 |
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Block | f-block |
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Electron configuration | [Xe] 4f7 6s2 |
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Electrons per shell | 2, 8, 18, 25, 8, 2 |
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Phase at STP | solid |
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Melting point | 1099 K (826 °C, 1519 °F) |
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Boiling point | 1802 K (1529 °C, 2784 °F) |
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Density (near r.t.) | 5.244 g/cm3 |
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when liquid (at m.p.) | 5.13 g/cm3 |
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Heat of fusion | 9.21 kJ/mol |
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Heat of vaporization | 176 kJ/mol |
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Molar heat capacity | 27.66 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
863 |
957 |
1072 |
1234 |
1452 |
1796 |
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Oxidation states | 0,[3] +2, +3 (a mildly basic oxide) |
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Electronegativity | Pauling scale: 1.2 |
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Ionization energies | - 1st: 547.1 kJ/mol
- 2nd: 1085 kJ/mol
- 3rd: 2404 kJ/mol
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Atomic radius | empirical: 180 pm |
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Covalent radius | 198±6 pm |
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Spectral lines of europium |
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Natural occurrence | primordial |
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Crystal structure | body-centered cubic (bcc) |
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Thermal expansion | poly: 35.0 µm/(m⋅K) (at r.t.) |
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Thermal conductivity | est. 13.9 W/(m⋅K) |
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Electrical resistivity | poly: 0.900 µΩ⋅m (at r.t.) |
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Magnetic ordering | paramagnetic[4] |
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Molar magnetic susceptibility | +34000.0×10−6 cm3/mol[5] |
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Young's modulus | 18.2 GPa |
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Shear modulus | 7.9 GPa |
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Bulk modulus | 8.3 GPa |
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Poisson ratio | 0.152 |
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Vickers hardness | 165–200 MPa |
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CAS Number | 7440-53-1 |
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Naming | after Europe |
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Discovery and first isolation | Eugène-Anatole Demarçay (1896, 1901) |
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Main isotopes[6] |
Decay |
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abundance |
half-life (t1/2) |
mode |
product |
150Eu |
synth |
36.9 y |
ε |
150Sm |
151Eu |
47.8% |
5×1018 y |
α |
147Pm |
152Eu |
synth |
13.54 y |
ε |
152Sm |
β− |
152Gd |
153Eu |
52.2% |
stable |
154Eu |
synth |
8.59 y |
β− |
154Gd |
155Eu |
synth |
4.76 y |
β− |
155Gd |
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Category: Europium | references |