Nb 41

Niobium (Nb)

transition-metal
Period: 5 Group: 5 Block: s

Solid

Standard Atomic Weight

92.90637 u

Electron configuration

[Kr] 5s1 4d4

Melting point

2476.85 °C (2750 K)

Boiling point

4743.85 °C (5017 K)

Density

8570 kg/m³

Oxidation states

−3, −1, 0, +1, +2, +3, +4, +5

Electronegativity (Pauling)

1.6

Ionization energy (1st)

Discovery year

1801

Atomic radius

145 pm

Details

Name origin From Niobe; daughter of the mythical Greek king Tantalus.
Discovery country England
Discoverers Charles Hatchet

Niobium is a refractory transition metal of group 5, chemically similar to tantalum and commonly occurring with it in oxide minerals. It is valued for its ability to strengthen steel at very small additions and for forming superconducting intermetallic compounds. In most compounds niobium is pentavalent, but lower oxidation states are well established, especially in halides and cluster chemistry.

Niobium is a shiny, white, soft, and ductile metal, and takes on a bluish cast when exposed to air at room temperatures for a long time. The metal starts to oxidize in air at 200°C, and when processed at even moderate temperatures must be placed in a protective atmosphere.

The name derives from the Greek mythological character Niobe, who was the daughter of Tantalus, because the elements niobium and tantalum were originally thought to be identical. Niobium was discovered in a black mineral from America called columbite by the British chemist and manufacturer Charles Hatchett in 1801 and he called the element columbium. In 1809, the English chemist William Hyde Wollaston claimed that columbium and tantalum were identical.

Forty years later, the German chemist and pharmacist, Heinrich Rose, determined that they were two different elements in 1846 and gave the name niobium because it was so difficult to distinguish it from tantalum. The name columbium continued to be used in America and niobium in Europe until IUPAC adopted the name niobium in 1949. Niobium was first isolated by the chemist C. W. Blomstrand in 1846.

The story of niobium's discovery is a bit confusing. The first governor of Connecticut, John Winthrop the Younger, discovered a new mineral around 1734. He named the mineral columbite ((Fe, Mn, Mg)(Nb, Ta)2O6) and sent a sample of it to the British Museum in London, England. The columbite sat in the museum's mineral collection for years until it was analyzed by Charles Hatchett in 1801. Hatchett could tell that there was an unknown element in the columbite, but he was not able to isolate it. He named the new element columbium. The fate of columbium took a drastic turn in 1809 when William Hyde Wollaston, an English chemist and physicist, compared the minerals columbite and tantalite ((Fe, Mn)(Ta, Nb)2O6) and declared that columbium was actually the element tantalum. This confusion arose because tantalum and niobium are similar metals, are always found together and are very difficult to isolate.

Niobium was rediscovered and renamed by Heinrich Rose in 1844 when he produced two new acids, niobic acid and pelopic acid, from samples of columbite and tantalite. These acids are very similar to each other and it took another twenty-two years and a Swiss chemist named Jean Charles Galissard de Marignac to prove that these were two distinct chemicals produced from two different elements. Metallic niobium was finally isolated by the Swedish chemist Christian Wilhelm Blomstrand in 1864. Today, niobium is primarily obtained from the minerals columbite and pyrochlore ((Ca, Na)2Nb2O6(O, OH, F)).

Named after Niobe, the daughter of Tantalu. Discovered in 1801 by Hatchett in an ore sent to England. The metal was first prepared in 1864 by Blomstrand, who reduced the chloride by heating it in a hydrogen atmosphere. The name niobium was adopted by the International Union of Pure and Applied Chemicstry (IUPAC) in 1950 after 100 years of controversy. Many leading chemical societies and government organizations refer to it by this name. Most metallurgists, leading metal societies, and all but one of the leading U.S. commercial producers, however, still refer to the metal as "columbium."

Images

Properties

Physical

Atomic radius (empirical) 145 pm
Covalent radius 164 pm
Van der Waals radius 207 pm
Metallic radius 134 pm
Density
Molar volume 0.0108 L/mol
Phase at STP solid
Melting point 2476.85 °C
Boiling point 4743.85 °C
Thermal conductivity 53.7 W/(m·K)
Specific heat capacity 0.265 J/(g·K)
Molar heat capacity 24.6 J/(mol·K)
Crystal structure bcc

Chemical

Electronegativity (Pauling) 1.6
Electronegativity (Allen) 1.41
Electron affinity
Ionization energy (1st)
Ionization energy (2nd)
Ionization energy (3rd)
Ionization energy (4th)
Ionization energy (5th)
Oxidation states −3, −1, 0, +1, +2, +3, +4, +5
Valence electrons 5
Electron configuration
Electron configuration (semantic)

Thermodynamic

Heat of fusion 0.27776338 eV
Heat of vaporization 7.151371 eV
Heat of sublimation 7.617764 eV
Heat of atomization 7.617764 eV
Atomization enthalpy

Nuclear

Stable isotopes 1
Discovery year 1801

Abundance

Abundance (Earth's crust) 20 mg/kg
Abundance (ocean)

Reactivity

N/A

Crystal Structure

Lattice constant a 330 pm

Electronic Structure

Electrons per shell 2, 8, 18, 12, 1

Identifiers

CAS number 7440-03-1
Term symbol
InChI InChI=1S/Nb
InChI Key GUCVJGMIXFAOAE-UHFFFAOYSA-N

Electron Configuration Measured

Ion charge
Protons 41
Electrons 41
Charge Neutral
Configuration Nb: 4d⁴ 5s¹
Electron configuration
Measured
[Kr] 4d⁴ 5s¹
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁴ 5s¹
Orbital diagram
1s
2/2
2s
2/2
2p
6/6
3s
2/2
3p
6/6
4s
2/2
3d
10/10
4p
6/6
5s
1/2 1↑
4d
4/10 4↑
Total electrons: 41 Unpaired: 5 ?

Atomic model

Protons 41
Neutrons 52
Electrons 41
Mass number 93
Stability Stable

Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.

Schematic atomic model, not to scale.

Atomic Fingerprint

Emission / Absorption Spectrum

24 / 24 (22 with intensity)
Measured
Emission Visible: 380–750 nm

Isotope Distribution

Monoisotopic element
Only naturally occurring isotope: 93 — 100.0000%
93100.0000%Mass numberNatural abundance (%)
Mass numberAtomic mass (u)Natural abundanceHalf-life
93 Stable92.906373 ± 0.000002100.0000%Stable
Measured

Phase / State

1 atm / 101.325 kPa
Solid 25 °C (298.15 K)

Reason: 2451.8 °C below melting point (2476.85 °C)

Melting point 2476.85 °C
Boiling point 4743.85 °C
Below melting by 2451.8 °C
0 K Current temperature: 25 °C 6000 K
Phase timeline

Schematic, not to scale

Solid
Liquid
Gas
Melting
Boiling
25°C
Solid
Liquid
Gas
Current

Phase transition points

Melting point Literature
2476.85 °C
Boiling point Literature
4743.85 °C
Current phase Calculated
Solid

Transition energies

Heat of fusion Literature
0.27776338 eV

Energy required to melt 1 mol at melting point

Heat of vaporization Literature
7.151371 eV

Energy required to vaporize 1 mol at boiling point

Heat of sublimation Literature
7.617764 eV

Energy required to sublime 1 mol at sublimation point

Density

Reference density Literature
8570 kg/m³

At standard conditions

Current density Calculated
8570 kg/m³

At standard conditions

Atomic Spectra

Showing 10 of 41 Atomic Spectra. Sorted by ion charge (ascending).

Lines Holdings ?

IonChargeTotal linesTransition probabilitiesLevel designations
Nb I 050900
Nb II +115000
Nb III +210800
Nb IV +3819819819
Nb V +41200
NIST Lines Holdings →

Levels Holdings ?

IonChargeLevels
Nb I 0395
Nb II +1354
Nb III +2189
Nb IV +3183
Nb V +431
Nb VI +5105
Nb VII +632
Nb VIII +72
Nb IX +82
Nb X +92
NIST Levels Holdings →
41 Nb 92.90637

Niobium — Atomic Orbital Visualizer

[Kr]5s14d4
Energy levels 2 8 18 12 1
Oxidation states -3, -1, 0, +1, +2, +3, +4, +5
HOMO 5s n=5 · l=0 · m=0
Niobium — Atomic Orbital Visualizer Preview
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41 Nb 92.90637

Niobium — Crystal Structure Visualizer

Body-Centered Cubic · Pearson cI2
Experimental
Pearson cI2
Coord. № 8
Packing 68.000%
Niobium — Crystal Structure Visualizer Preview
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Ionic Radii

ChargeCoordinationSpinRadius
+36N/A72 pm
+46N/A68 pm
+48N/A79 pm
+54N/A48 pm
+56N/A64 pm
+57N/A69 pm
+58N/A74 pm

Compounds

Nb
92.906 u
Nb
94.907 u
Nb
89.911 u
Nb
93.907 u
Nb
96.908 u
Nb
87.918 u
Nb
88.913 u
Nb
97.910 u
Nb
95.908 u
Nb
92.906 u
Nb
91.907 u
Nb+5
92.906 u
Nb+3
92.906 u
Nb+2
92.906 u

Isotopes (1)

Eighteen isotopes of niobium are known. The metal can be isolated from tantalum, and prepared in several ways.

Mass numberAtomic mass (u)Natural abundanceHalf-lifeDecay mode
93 Stable92.906373 ± 0.000002100.0000%Stable
stable
93 Stable
Atomic mass (u) 92.906373 ± 0.000002
Natural abundance 100.0000%
Half-life Stable
Decay mode
stable

Spectral Lines

Wavelength (nm)IntensityIon stageTypeTransitionAccuracySource
382.5416 nm5000Nb IVemission4d.5d 3P → 4d.6p 1P*MeasuredNIST
382.5694 nm200000Nb IVemission4d.6p 1F* → 4d.6d 3DMeasuredNIST
382.5875 nm250000Nb IVemission4d.6p 3P* → 4d.6d 3DMeasuredNIST
383.106 nm15000Nb IVemission4d.5d 3D → 4d.6p 1D*MeasuredNIST
385.2874 nm60000Nb IVemission4d.6p 3P* → 4d.6d 3DMeasuredNIST
385.5325 nm10000Nb IVemission4d.6p 1P* → 4d.6d 3PMeasuredNIST
386.9546 nm8000Nb IVemission4d.6p 3P* → 4d.6d 1PMeasuredNIST
387.5455 nm100000Nb IVemission4d.5d 3G → 4d.6p 1D*MeasuredNIST
388.2203 nm60000Nb IVemission4d.6p 1P* → 4d.6d 1SMeasuredNIST
389.8028 nm100000Nb IVemission4d.5d 3S → 4d.6p 3P*MeasuredNIST
390.0115 nm25000Nb IVemission4d.6p 3P* → 4d.6d 3DMeasuredNIST
391.6922 nm8000Nb IVemission4d.5d 3F → 4d.6p 1F*MeasuredNIST
392.1878 nm5000Nb IVemission4d.5d 1P → 4d.6p 3D*MeasuredNIST
394.057 nm25000Nb IVemission4d.6p 3P* → 4d.6d 3DMeasuredNIST
394.3315 nm20000Nb IVemission4d.5d 3F → 4d.6p 3F*MeasuredNIST
398.5759 nm5000Nb IVemission4d.(2D<3/2>).6s 2[3/2] → 4d.6p 1P*MeasuredNIST
400.1839 nm4000Nb IVemission4d.6p 3P* → 4d.6d 3DMeasuredNIST
403.2233 nm40000Nb IVemission4d.5d 3F → 4d.6p 3D*MeasuredNIST
404.998 nm10000Nb IVemission4d.5d 3F → 4d.6p 3F*MeasuredNIST
405.2616 nm15000Nb IVemission4d.5d 1P → 4d.6p 1D*MeasuredNIST
406.3412 nm200000Nb IVemission4d.5d 3F → 4d.6p 3F*MeasuredNIST
406.4694 nmN/ANb IVemission4d.6p 1P* → 4d.6d 1DMeasuredNIST
409.6529 nm7000Nb IVemission4d.6p 3P* → 4d.6d 3DMeasuredNIST
459.6 nmN/AID 841emission2p 2P* → 2s 2SMeasuredNIST

Extended Properties

Covalent Radii (Extended)

Covalent radius (Pyykkö)  
Covalent radius (Pyykkö, double)  
Covalent radius (Pyykkö, triple)  

Van der Waals Radii

Batsanov  
Alvarez  
UFF  
MM3  

Atomic & Metallic Radii

Atomic radius (Rahm)  
Metallic radius (C12)  

Numbering Scales

Mendeleev
Pettifor
Glawe

Electronegativity Scales

Ghosh
Miedema
Gunnarsson–Lundqvist
Robles–Bartolotti

Polarizability & Dispersion

Dipole polarizability  
Dipole polarizability (unc.)  
C₆ (Gould–Bučko)  

Miedema Parameters

Miedema molar volume  
Miedema electron density

Supply Risk & Economics

Production concentration
Relative supply risk
Reserve distribution
Political stability (top producer)
Political stability (top reserve)

Phase Transitions & Allotropes

Melting point2750.15 K
Boiling point5014.15 K

Oxidation State Categories

−1 extended
+4 extended
+2 extended
+3 extended
+1 extended
0 extended
+5 main
−3 extended

Advanced Reference Data

Screening Constants (10)
nOrbitalσ
1s0.8577
2p4.0178
2s10.8748
3d14.753
3p16.3844
3s15.8285
4d29.7624
4p26.9156
4s25.7172
5s35.079
Crystal Radii Detail (7)
ChargeCNSpinrcrystal (pm)Origin
3VI86
4VI82from r^3 vs V plots, estimated,
4VIII93
5IV62calculated,
5VI78
5VII83calculated,
5VIII88
Isotope Decay Modes (67)
IsotopeModeIntensity
79p
79B+
79B+p
80p
80B+
80B+p
81p
81B+
81B+p
82B+100%
X‑ray Scattering Factors (757)
Energy (eV)f₁f₂
0.50.09113
0.50790.09258
0.5160.09406
0.52420.09557
0.53250.0971
0.54090.09865
0.54950.10023
0.55820.10161
0.56710.103
0.57610.10441

Additional Data

Sources

Sources of this element.

The element is found in niobite (or columbite), niobite-tantalite, parochlore, and euxenite. Large deposits of niobium have been found associated with carbonatites (carbon-silicate rocks), as a constituent of parochlore. Extensive ore reserves are found in Canada, Brazil, Nigeria, Zaire, and in Russia.

References (1)

References

(9)
2 Atomic Mass Data Center (AMDC), International Atomic Energy Agency (IAEA)
Nb

The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.

3 IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW)
Niobium

Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.

4 IUPAC Periodic Table of the Elements and Isotopes (IPTEI)

The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.

License note: Copyright (c) 2020 International Union of Pure and Applied Chemistry. The International Union of Pure and Applied Chemistry (IUPAC) contribution within Pubchem is provided under a CC-BY-NC-ND 4.0 license, unless otherwise stated.
5 Jefferson Lab, U.S. Department of Energy
Niobium

Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/

License note: Please see citation and linking information: https://education.jlab.org/faq/index.html
6 Los Alamos National Laboratory, U.S. Department of Energy
Niobium

The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.

7 NIST Physical Measurement Laboratory
Niobium

The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database

8 PubChem Elements
Niobium

This section provides all form of data related to element Niobium.

9 PubChem Elements
Niobium

The element property data was retrieved from publications.

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