![Template:Infobox element/symbol-to-top-image/alt](https://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Niobium_crystals_and_1cm3_cube.jpg/220px-Niobium_crystals_and_1cm3_cube.jpg) |
Niobium |
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Pronunciation | (ny-OH-bee-əm) |
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Appearance | gray metallic, bluish when oxidized |
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Standard atomic weight Ar, std(Nb) | 7001929063700000000♠92.90637(1)[1] |
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Niobium in the periodic 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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Phase at 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
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1 k
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10 k
|
100 k
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at T (K)
|
2942
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3207
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3524
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3910
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4393
|
5013
|
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Atomic properties |
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Oxidation states | −3, −1, +1, +2, +3, +4, +5 (a mildly acidic 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 Cubic bouk-centred creestal structur for niobium |
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Speed o soond thin 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 | after Niobe in Greek meethologie, dochter o Tantalus (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 distinct element bi | Heinrich Rose (1844) |
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Main isotopes o niobium |
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Isotope
|
Abundance
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Hauf-life (t1/2)
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Decay mode
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Product
|
90Nb
|
syn
|
15 h
|
β+
|
90Zr
|
91Nb
|
syn
|
680 y
|
ε
|
91Zr
|
91mNb
|
syn
|
61 d
|
IT
|
91Nb
|
92m1Nb
|
syn
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10 d
|
ε
|
92Zr
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γ
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–
|
92Nb
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trace
|
3.47×107 y
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ε
|
92Zr
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γ
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–
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93Nb
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100%
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stable
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93mNb
|
syn
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16 y
|
IT
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93Nb
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94Nb
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trace
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20.3×103 y
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β−
|
94Mo
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γ
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–
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95Nb
|
syn
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35 d
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β−
|
95Mo
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γ
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–
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95mNb
|
syn
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4 d
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IT
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95Nb
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96Nb
|
syn
|
24 h
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β−
|
96Mo
| |
| references |