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Ti
22
V
23
Cr
24
Zr
40
Nb
41
Mo
42
Hf
72
Ta
73
W
74

 

Periodic table

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Niob

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Niobium

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Niobium

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Niobij

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Niobio

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Niobio

 

Nb
Nb
Niobium

PERIODIC TABLE OF THE ELEMENTS

NIOBIUM

TRANSITION ELEMENT: VANADIUM GROUP

 

Atomic number:41

Group numbers:5

Period:5

Electronic configuration:[Kr] 4d4 5s1

Formal oxidation number:+3 +5

Electronegativities:1.6

Atomic radius / pm:142.9

Relative atomic mass:92.90638 ± 0.00002

 

Niobium was discovered by Charles Hatchett (GB) in 1801. The origin of the name comes from the Greek word Niobe meaning daughter of Tantalus in Greek mythology (tantalum is closely related to niobium in the periodic table). It is a shiny white, soft, ductile metal. Exposed surfaces form oxide film. Niobium occurs in a mineral columbite. It is used in stainless steel alloys for nuclear reactors, jets and missiles. It is used as an alloy with iron and nickel. It can be used in nuclear reactors and is known to be superconductive when alloyed with tin, aluminium or zirconium.

PHYSICAL PROPERTIES

Density / g dm-3:8570 (293 K)

 7830 (m.p.)

Molar volume / cm3mol-1:10.84 (293 K)

 11.87 (m.p.)

Electrical resistivity / μΩcm:12.5 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m-1K-1:53.7

Melting point / °C:2477

Boiling point / °C:4744

Heat of fusion / kJ mol-1:27.2

Heat of vaporization / kJ mol-1:680.19

Heat of atomization / kJ mol-1:722.819

IONIZATION ENERGIES

First ionization energy / kJ mol-1:652.13

Second ionization energy / kJ mol-1:1381.68

Third ionization energy / kJ mol-1:2416.01

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:11

in the oceans / ppm:0.00001

CRYSTALLOGRAPHIC DATA

body-centered cubic

Crystal structure:

body-centered cubic

Unit-cell dimensions / pm:

a=329.86

Space group:

Im3m

ISOTOPES

IsotopeRelative atomic massMass percent (%)
93Nb92.906378(2)100

REDUCTION POTENTIALS

Balanced half-reaction Eo / V
NbV + 2e- = NbIII- 0.373 (6 mol dm-3 H2SO4)
Nb3+ + 3e- = Nb(s)- 1.1
Nb2O5(s) + 10H+ + 10e- = 2Nb(s) + 5H2O- 0.65
NbO3+ + 2H+ + 2e- = Nb3+ + H2O- 0.343
NbO(SO4)2- + 2H+ + 2e- = Nb3+ + H2O + 2SO42-- 0.1
NbO(SO4)2- + 2H+ + 5e- = Nb(s) + H2O + 2SO42-- 0.63

 

40 Zirconium <=
41 Niobium
=> 42 Molybdenum