Niob (Nb)

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Niob 41Nb92.906

1801 von C. Hatchett in London, UK, entdeckt.

[Griechisch, Niobe = Tochter des Tantalus]

French: Niobium
English: Niobium
Italian: Niobio
Spanish: Niobio

Beschreibung: Blankes, silberfarbiges Metall, in reinem Zustand weich. Korrodiert nicht, da es durch eine Oxidhaut passiviert wird. Wird durch heiße konzentrierte Säuren angegriffen, nicht durch geschmolzene Alkalien. Verwendung in rostfreien Stählen.

 

 

Niob single crystal properties

State: single crystal
Crystal structure: bcc
Production method: Floating Zone
Standard size: diameter 8-12mm
thickness 1-2mm
Orientation: (100), (110) and (111)
Orientation accuracy: <2°, <1°, <0.4° or <0.1°
Polishing: as cut, one or two sides polished
Roughness of surface: <0.03µm
Purity: 99.99%
Typical analysis (ppm): C 3
H < 1
O 9
N < 5
Cu 1.60
Fe 1.80
Ni < 1
Pb 0.30
Si 0.30

 
Ga, Hf and Ta are below the detection limit
 

Materials properties

Density: 8.4 g/cm3
Melting point: 2467.85 °C / 2741 °K
Boiling point: 4741.85 °C / 5015 °K
Molar volume: 10.84 cm3
Thermal conductivity: 53.7 [300 K] Wm-1K-1
Coefficient of linear thermal expansion: 7.07 x 10-6 K-1
Electrical resistivity: 12.5x 10-8 [273 K] Wm
Mass magnetic susceptibility: +2.76 x 10-8(s) kg-1m3
Young's modulus: 104.9 GPa
Rigidity modulus: 37.5 GPa
Bulk modulus: 170.3 GPa
Poisson's ratio: 0.397 GPa
Radii: Nb5+ 69; Nb4+ 74; atomic 143; covalent 134
Electronegativity: 1.6 (Pauling); 1.23 (Allred); 4.0 eV (absolute)
Effective nuclear charge: 3.30 (Slater); 6.70 (Clementi); 9.60 (Froese-Fischer)
Number of Isotopes (incl. nuclear isomers): 31
Issotope mass range: 86 -> 103
Crystal structure, (cell dimentions / pm), space group bcc
X-ray diffraction: mass absorption coefficients: CuKα 153 (µ/r) / cm2g-1
MoKα 17.1 (µ/r) / cm2g-1
Neutron scattering length: 0.7054 b/10-12 cm
Thermal neutron capture cross-section: 1.15 sa / barns

 

Biological data

Biological role: none
Toxicity  
Toxic intake: n.a.
Lethal intake: LD50 (chloride, oral, rat)= 1500 mg kg-1
Hazards: Niobium and its compounds may be toxic but there are no reports of humans beeing poisoned. Niobium dust causes eye and skin irritation.
Level in humans  
Blood: 0.005 mg dm-3
Bone: <0.07 p.p.m.
Liver: 0.14 p.p.m.
Muscle: 0.14 p.p.m.
Daily dietary intake: 0.02 - 0.6 mg
Total mass of element in average [70 kg] person: < 1.5 mg

 

Geological data

MineralFormulaDensityHardnessCrystal apperance
Betafite (Ca, U)2(Ti, Nb, Ta)2O6(OH) 4.5 4 - 5.5 cub., waxy/vit. black/greenish
Columbite (Fe, Mn)(Nb, Ta)2O6 varies c. 6 orth., opaque sub.met. lustre
Fergusonite YNbO4) 5.7 5.5 - 6.5 tet., vitreous, sub-met. black
Samarskite (Y, Ce, U, Fe)3(Nb, Ta, Ti)5O16 5.69 5 - 6 orth., vitreous/resinous black

 

Chief ore: columbite, samarskite, betafite; obtained as a by-product of tin-extraction.
World production: 15 000 tonnes/year
Main mining areas: Australia, Zaire, Brazil, Russia, Norway, Canada, Madagascar
Reserves: n.a.
Specimen: available as foil, powder, rod, turnings or wire. Safe.

 

Abundances  
Sun: 79 (relative to H = 1 x 1012)
Earth's crust: 20 p.p.m.
Seawater:  
Residence time:  
Classification:  
Oxidation state: V

Übersicht der Elemente mit Zugang zu unserem Shop

1 18
H
 2 13 14 15 16 17
He
Li Be B C
N
O
F
Ne
Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S
Cl
Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se
Br
Kr
Rb Sr Y Zr Nb Mo
Tc
 Ru Rh Pd Ag Cd In Sn Sb Te I
Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi
Po
At
Ra
Fr
Ra
Ac
Ce Pr Nd
Pm
 Sm Eu Gd Tb Dy Ho Er Tm Yb Lu


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