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Pronunciation | (SEER-ee-əm) |
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Appearance | silvery white |
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| 140.116(1)[1] |
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Atomic number (Z) | 58 |
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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] 4f1 5d1 6s2[2] |
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Electrons per shell | 2, 8, 18, 19, 9, 2 |
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Phase at STP | solid |
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Melting point | 1068 K (795 °C, 1463 °F) |
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Boiling point | 3716 K (3443 °C, 6229 °F) |
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Density (near r.t.) | 6.770 g/cm3 |
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when liquid (at m.p.) | 6.55 g/cm3 |
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Heat of fusion | 5.46 kJ/mol |
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Heat of vaporization | 398 kJ/mol |
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Molar heat capacity | 26.94 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
1992 |
2194 |
2442 |
2754 |
3159 |
3705 |
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Oxidation states | +1, +2, +3, +4 (a mildly basic oxide) |
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Electronegativity | Pauling scale: 1.12 |
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Ionization energies | - 1st: 534.4 kJ/mol
- 2nd: 1050 kJ/mol
- 3rd: 1949 kJ/mol
- (more)
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Atomic radius | empirical: 181.8 pm |
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Covalent radius | 204±9 pm |
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Spectral lines of cerium |
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Natural occurrence | primordial |
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Crystal structure | double hexagonal close-packed (dhcp) β-Ce |
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Crystal structure | face-centered cubic (fcc) γ-Ce |
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Speed of sound thin rod | 2100 m/s (at 20 °C) |
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Thermal expansion | γ, poly: 6.3 µm/(m⋅K) (at r.t.) |
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Thermal conductivity | 11.3 W/(m⋅K) |
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Electrical resistivity | β, poly: 828 nΩ⋅m (at r.t.) |
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Magnetic ordering | paramagnetic[3] |
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Molar magnetic susceptibility | (β) +2450.0×10−6 cm3/mol (293 K)[4] |
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Young's modulus | γ form: 33.6 GPa |
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Shear modulus | γ form: 13.5 GPa |
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Bulk modulus | γ form: 21.5 GPa |
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Poisson ratio | γ form: 0.24 |
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Mohs hardness | 2.5 |
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Vickers hardness | 210–470 MPa |
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Brinell hardness | 186–412 MPa |
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CAS Number | 7440-45-1 |
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Naming | after dwarf planet Ceres, itself named after Roman deity of agriculture Ceres |
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Discovery | Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger (1803) |
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First isolation | Carl Gustaf Mosander (1838) |
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Main isotopes[5] |
Decay |
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abundance |
half-life (t1/2) |
mode |
product |
134Ce |
synth |
3.16 d |
ε |
134La |
136Ce |
0.186% |
stable |
138Ce |
0.251% |
stable |
139Ce |
synth |
137.640 d |
ε |
139La |
140Ce |
88.4% |
stable |
141Ce |
synth |
32.501 d |
β− |
141Pr |
142Ce |
11.1% |
stable |
143Ce |
synth |
33.039 h |
β− |
143Pr |
144Ce |
synth |
284.893 d |
β− |
144Pr |
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Category: Cerium | references |