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| Thulium |
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| Pronunciation | (THEW-lee-əm) |
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| Appearance | silvery gray |
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| Standard atomic weight Ar, std(Tm) | 7002168934218000000♠168.934218(6)[1] |
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| Thulium in the periodic cairt |
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| -
↑
Tm
↓
Md | | erbium ← thulium → ytterbium |
|
|
| Atomic nummer (Z) | 69 |
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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] 4f13 6s2 |
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| Electrons per shell | 2, 8, 18, 31, 8, 2 |
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| Pheesical properties |
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| Phase at STP | solit |
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| Meltin pynt | 1818 K (1545 °C, 2813 °F) |
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| Bylin pynt | 2223 K (1950 °C, 3542 °F) |
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| Density (near r.t.) | 9.32 g/cm3 |
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| when liquid (at m.p.) | 8.56 g/cm3 |
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| Heat o fusion | 16.84 kJ/mol |
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| Heat o vapourisation | 247 kJ/mol |
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| Molar heat capacity | 27.03 J/(mol·K) |
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Vapour pressur| P (Pa) | 1 | 10 | 100 | 1 k | 10 k | 100 k |
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| at T (K) | 1117 | 1235 | 1381 | 1570 | (1821) | (2217) |
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|
| Atomic properties |
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| Oxidation states | +2, +3 (a basic oxide) |
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| Electronegativity | Pauling scale: 1.25 |
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| Atomic radius | empirical: 176 pm |
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| Covalent radius | 190±10 pm |
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 Colour lines in a spectral rangeSpectral lines o thulium |
| Ither properties |
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| Naitural occurrence | primordial |
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| Creestal structur | hexagonal close-packed (hcp) |
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| Thermal expansion | (r.t.) (poly)
13.3 µm/(m·K) |
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| Thermal conductivity | 16.9 W/(m·K) |
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| Electrical resistivity | (r.t.) (poly) 676 n Ω·m |
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| Magnetic orderin | paramagnetic at 300 K |
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| Young's modulus | 74.0 GPa |
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| Shear modulus | 30.5 GPa |
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| Bulk modulus | 44.5 GPa |
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| Poisson ratio | 0.213 |
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| Vickers haurdness | 520 MPa |
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| Brinell haurdness | 471 MPa |
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| CAS Nummer | 7440-30-4 |
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| History |
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| Diskivery | Per Teodor Cleve (1879) |
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| First isolation | Per Teodor Cleve (1879) |
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| Main isotopes o thulium |
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| Isotope | Abundance | Hauf-life (t1/2) | Decay mode | Product |
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| 167Tm | syn | 9.25 d | ε | 167Er |
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| 168Tm | syn | 93.1 d | ε | 168Er |
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| 169Tm | 100% | - | (α) | 165Ho |
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| 170Tm | syn | 128.6 d | β− | 170Yb |
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| 171Tm | syn | 1.92 y | β− | 171Yb |
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|
| Decay modes in parentheses are predictit, but hae nae yet been observed |
| | references |
