Niobium, 41 Nb Niobium Pronunciation (ny-OH -bee-əm ) Appearance gray metallic, bluish when oxidized Standard atomic weight A r, std (Nb) 7001929063700000000♠ 92.90637 (1)[1] Niobium in the periodic cairt
Atomic nummer (Z ) 41 Group group 5 Period period 5 Block d-block Element category Transeetion metalElectron confeeguration [Kr] 4d4 5s1 Electrons per shell 2, 8, 18, 12, 1 Pheesical properties Phase at STP solid Meltin pynt 2750 K (2477 °C, 4491 °F) Bylin pynt 5017 K (4744 °C, 8571 °F) Density (near r.t. ) 8.57 g/cm3 Heat o fusion 30 kJ/mol Heat o vapourisation 689.9 kJ/mol Molar heat capacity 24.60 J/(mol·K) Vapour pressur
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
2942
3207
3524
3910
4393
5013
Atomic properties Oxidation states −3, −1, +1, +2, +3, +4, +5 (a mildly acidic oxide) Electronegativity Pauling scale: 1.6 Ionisation energies 1st: 652.1 kJ/mol 2nd: 1380 kJ/mol 3rd: 2416 kJ/mol Atomic radius empirical: 146 pm Covalent radius 164±6 pm Colour lines in a spectral range Spectral lines o niobium Ither properties Naitural occurrence primordial 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]]
Speed o soond thin rod 3480 m/s (at 20 °C) Thermal expansion 7.3 µm/(m·K) Thermal conductivity 53.7 W/(m·K) Electrical resistivity 152 nΩ·m (at 0 °C) Magnetic orderin paramagnetic Young's modulus 105 GPa Shear modulus 38 GPa Bulk modulus 170 GPa Poisson ratio 0.40 Mohs haurdness 6.0 Vickers haurdness 870–1320 MPa Brinell haurdness 735–2450 MPa CAS Nummer 7440-03-1 History Namin after Niobe in Greek meethologie, dochter o Tantalus (tantalum) Diskivery Charles Hatchett (1801) First isolation Christian Wilhelm Blomstrand (1864) Recognised as a distinct element bi Heinrich Rose (1844) Main isotopes o niobium
Isotope
Abundance
Hauf-life (t 1/2 )
Decay mode
Product
90 Nb
syn
15 h
β+
90 Zr
91 Nb
syn
680 y
ε
91 Zr
91m Nb
syn
61 d
IT
91 Nb
92m1 Nb
syn
10 d
ε
92 Zr
γ
–
92 Nb
trace
3.47×107 y
ε
92 Zr
γ
–
93 Nb
100%
stable
93m Nb
syn
16 y
IT
93 Nb
94 Nb
trace
20.3×103 y
β−
94 Mo
γ
–
95 Nb
syn
35 d
β−
95 Mo
γ
–
95m Nb
syn
4 d
IT
95 Nb
96 Nb
syn
24 h
β−
96 Mo
| references
Niobium , umwhile columbium , is a chemical element wi the seembol Nb (umwhile Cb ) an atomic nummer 41. It is a saft, grey, ductile transeetion metal, whilk is aften foond in the pyrochlore mineral, the main commercial soorce for niobium, an columbite. The name comes frae Greek meethology : Niobe , dauchter o Tantalus .
↑ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)" . Pure and Applied Chemistry . 88 (3): 265–91. doi :10.1515/pac-2015-0305 .