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| Niobium |
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| Pronunciation | /naɪˈoʊbiəm/(ny-OH-bee-əm) |
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| Appearance | gray metallic, bluish when oxidized |
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| Standard atomic weightAr, std(Nb) | 7001929063700000000♠92.90637(1)[1] |
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| Niobium in theperiodic cairt |
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| Atomic nummer(Z) | 41 |
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| Group | group 5 |
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| Period | period 5 |
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| Block | d-block |
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| Element category | Transeetion metal |
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| Electron confeeguration | [Kr] 4d4 5s1 |
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| Electrons per shell | 2, 8, 18, 12, 1 |
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| Pheesical properties |
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| Phaseat STP | solid |
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| Meltin pynt | 2750 K(2477 °C,4491 °F) |
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| Bylin pynt | 5017 K(4744 °C,8571 °F) |
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| Density(near r.t.) | 8.57 g/cm3 |
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| Heat o fusion | 30 kJ/mol |
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| Heat o vapourisation | 689.9 kJ/mol |
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| Molar heat capacity | 24.60 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) | 2942 | 3207 | 3524 | 3910 | 4393 | 5013 |
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| Atomic properties |
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| Oxidation states | −3, −1, +1, +2, +3, +4,+5 (a mildlyacidic oxide) |
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| Electronegativity | Pauling scale: 1.6 |
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| Ionisation energies | - 1st: 652.1 kJ/mol
- 2nd: 1380 kJ/mol
- 3rd: 2416 kJ/mol
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| Atomic radius | empirical:146 pm |
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| Covalent radius | 164±6 pm |
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 Colour lines in a spectral rangeSpectral lines o niobium |
| Ither properties |
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| Naitural occurrence | primordial |
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| Creestal structur | cubic bouk-centred [[File:cubic bouk-centred|frameless|alt=Cubic bouk-centred creestal structur for niobium|upright=0.23|Cubic bouk-centred creestal structur for niobium]] |
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| Speed o soondthin rod | 3480 m/s(at 20 °C) |
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| Thermal expansion | 7.3 µm/(m·K) |
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| Thermal conductivity | 53.7 W/(m·K) |
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| Electrical resistivity | 152 nΩ·m(at 0 °C) |
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| Magnetic orderin | paramagnetic |
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| Young's modulus | 105 GPa |
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| Shear modulus | 38 GPa |
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| Bulk modulus | 170 GPa |
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| Poisson ratio | 0.40 |
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| Mohs haurdness | 6.0 |
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| Vickers haurdness | 870–1320 MPa |
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| Brinell haurdness | 735–2450 MPa |
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| CAS Nummer | 7440-03-1 |
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| History |
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| Namin | afterNiobe in Greek meethologie, dochter oTantalus (tantalum) |
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| Diskivery | Charles Hatchett(1801) |
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| First isolation | Christian Wilhelm Blomstrand(1864) |
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| Recognised as a distinctelement bi | Heinrich Rose (1844) |
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| Mainisotopes o niobium |
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| |references |
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