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Terbium |
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Pronunciation | (TUR-bee-əm) |
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Appearance | silvery white |
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Standard atomic weight Ar, std(Tb) | 7002158925354000000♠158.925354(8)[1] |
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Terbium in the periodic cairt |
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Atomic nummer (Z) | 65 |
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Group | group n/a |
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Period | period 6 |
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Block | f-block |
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Element category | Lanthanide |
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Electron confeeguration | [Xe] 4f9 6s2 |
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Electrons per shell | 2, 8, 18, 27, 8, 2 |
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Pheesical properties |
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Phase at STP | solit |
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Meltin pynt | 1629 K (1356 °C, 2473 °F) |
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Bylin pynt | 3503 K (3230 °C, 5846 °F) |
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Density (near r.t.) | 8.23 g/cm3 |
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when liquid (at m.p.) | 7.65 g/cm3 |
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Heat o fusion | 10.15 kJ/mol |
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Heat o vapourisation | 293 kJ/mol |
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Molar heat capacity | 28.91 J/(mol·K) |
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Vapour pressur
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
1789 |
1979 |
(2201) |
(2505) |
(2913) |
(3491) |
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Atomic properties |
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Oxidation states | 0,[2] +1, +2, +3, +4 waikly basic |
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Electronegativity | Pauling scale: ? 1.2 |
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Atomic radius | empirical: 177 pm |
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Covalent radius | 194±5 pm |
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Spectral lines o terbium |
Ither properties |
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Naitural occurrence | primordial |
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Creestal structur | hexagonal close-packed (hcp) |
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Speed o soond thin rod | 2620 m/s (at 20 °C) |
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Thermal expansion | (r.t.) (α, poly) 10.3 µm/(m·K) |
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Thermal conductivity | 11.1 W/(m·K) |
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Electrical resistivity | (r.t.) (α, poly) 1.150 µ Ω·m |
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Magnetic orderin | paramagnetic at 300 K |
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Young's modulus | (α form) 55.7 GPa |
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Shear modulus | (α form) 22.1 GPa |
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Bulk modulus | (α form) 38.7 GPa |
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Poisson ratio | (α form) 0.261 |
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Vickers haurdness | 863 MPa |
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Brinell haurdness | 677 MPa |
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CAS Nummer | 7440-27-9 |
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History |
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Diskivery | Carl Gustaf Mosander (1842) |
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First isolation | Carl Gustaf Mosander (1842) |
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Main isotopes o terbium |
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Isotope |
Abundance |
Hauf-life (t1/2) |
Decay mode |
Product |
157Tb |
syn |
71 y |
ε |
157Gd |
158Tb |
syn |
180 y |
ε |
158Gd |
β− |
158Dy |
159Tb |
100% |
- |
(SF) |
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Decay modes in parentheses are predictit, but hae nae yet been observed |
| references |