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About Niobium

Niobium Bohr Model

Refractory metals, characterized by their high melting point and resistance to oxidation, share many other attributes and applications; niobium and tantalum, in particular, are so similar to each other in properties and natural occurrence that the two were not definitely proven to be distinct elements until 1866. Niobium was the first of the two to be identified, in 1801 by British chemist and mineralogist Charles Hatchett. While employed at the British Museum, Hatchett became intrigued by a mineral sample displayed in the collection that had been sent decades earlier from the American colonies by Connecticut governor John Winthrop. His analysis of the sample yielded a substance he believed contained a heretofore undiscovered element that he named “columbium” for Columbia, the symbolic female embodiment of the United States, and the mineral itself came to be called columbite. Hatchett’s discovery was refuted shortly thereafter by British chemist William Hyde Wollaston, who claimed that columbium was in fact the same element discovered in a different mineral by Swedish chemist Anders Gustaf Ekeberg. Hyde argued that “tantalum” (Ekeberg’s name for the element, inspired by Greek mythological figure Tantalus) should subsume columbium as the sole official name for the substance.

The debate was far from over. In 1845, German chemist Heinrich Rose analyzed the same mineral from Ekeberg’s experiment (which had subsequently been termed tantalite) and announced the sample contained two elements in addition to tantalum--which he fittingly named “pelopium” and “niobium” after Pelops and Niobe, the daughters of Tantalus. Though Rose was ultimately incorrect in classifying pelopium as the third element in the sample (rather than a mixture of the other two, as it turned out to be), the substance he called niobium was indeed a second, distinct element--the very same substance Hatchett had (correctly) identified as an element in 1801. The element itself was isolated in 1864 independently by both Christian Blomstrand and Jean Charles Galissard de Marignac, putting an end to the uncertainty about its identity, but not to the ambiguity surrounding its name; both niobium and columbium coexisted in common usage without any consensus. Despite the IUPAC’s 1950 decision in favor of niobium as its sole official name, it is still referred to as columbium in some circles.

The difficulty in distinguishing between niobium and tantalum was due not only to their chemical similarity but also to the fact that the two never occur independently from each other in nature; besides columbite and tantalite, the two elements are found together in the minerals euxenite, manganocolumbite and manganotantalite, aeschynite, samarskite, simpsonite, tapiolite, and pyrochlore, the main commercial source of niobium when extracted as ferroniobium. It is also commercially prepared as a byproduct of tin extraction. de Marignac’s method of separating niobium from tantalum via fractional crystallization remained the primary method for many years, though other techniques such as liquid-liquid extraction were subsequently developed, all made possible by the differing densities of the two metals, niobium’s density being about half that of tantalum’s.

A soft and shiny gray transition metal, niobium is ductile and malleable and can be cold worked over 90% before requiring annealing. Compared to other refractory metals, niobium has the lowest density, melting point, modulus of elasticity, and thermal conductivity, and the highest thermal expansion. A thin film of niobium oxide ranging from yellow-green to blue in appearance provides surface passivation that makes the metal resistant to corrosion and attack by acids. Paired with its high strength and melting point, niobium’s resistance to oxidation make it an important component of alloys and superalloys such as Inconel 718, C103, and ferroniobium for high temperature, high stress applications like combustion equipment, jet engines, rocket assemblies, gas pipeline production, and air frame systems of spacecraft. It is also used in nuclear reactors due to its low neutron absorption cross section. Adding niobium to carbon and alloy steels increase their strength, toughness, and machinability. Niobium alloys are often used for arc welding rods for stabilized grades of stainless steel and in the arc-tube seals of high pressure sodium vapor lamps; one of the first commercial uses for the metal was in incandescent lamp filaments before being supplanted by tungsten. Niobium is non-toxic and does not react with human tissue, and as such is commonly used in surgical implants and medical devices; it can be colored by anodization, and is used in some jewelry.

Niobium has the largest magnetic penetration depth of any element and, along with vanadium and technetium, is one of the three elemental type-II superconductors--materials that exhibit superconductivity in both strong electric currents and magnetic fields. Niobium-tin alloy (Nb3Sn) was the first such material to be discovered in 1961 at Bell Labs. Niobium-tin wires, niobium-zirconium wires, and niobium-titanium wires are used in the high power superconducting magnets in MRI scanners, nuclear magnetic resonance instruments, and CERN. Niobium oxide has been used in metallic glass and smart windows, and is increasingly used in electronics and optics due to its high dielectric constant; lithium niobium oxide (lithium niobate, or LiNBO) is a common non-linear optical crystal. Due to its similar properties and wider availability, niobium is a potential lower-cost substitute for tantalum used in capacitors and transistors in microelectronics.


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Niobium's main use is in alloys where it is used to produce arc-welding rods and corrosion-resistant steel. Other applications include its use in superconducting materials, electronics, optics, numismatics and jewelry. Niobium is the basis for various barium titanate compositions used as dielectric coatings in telecommunications and small advanced electronics, such as cell phones, pagers and laptop computers. High Purity (99.999%) Niobium Oxide (Nb2O5) PowderNiobium has medical research applications as well. Niobium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). High Purity (99.999%) Niobium (Nb) Sputtering TargetElemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Niobium nanoparticles and nanopowders are also available. Niobium oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Niobium fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Niobium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Niobium Properties

Niobium (Nb) atomic and molecular weight, atomic number and elemental symbolNiobium is a Block D, Group 5, Period 5 element. Niobium Bohr ModelThe number of electrons in each of niobium's shells is 2, 8, 18, 12, 1 and its electronic configuration is [Kr] 4d4 5s1.The niobium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-03-1, niobium has a gray metallic appearance. Elemental NiobiumNiobium has the largest magnetic penetration depth of any element and it's one of three elemental type II superconductors (along with vanadium and technetium). Niobium is found in the minerals pyrochlore, its main commercial source, and columbite. It is not found in nature as a free element. Niobium was first discovered by Charles Hatchett in 1801. The word Niobium originates from Niobe, daughter of mythical Greek king Tantalus.

Symbol: Nb
Atomic Number: 41
Atomic Weight: 92.90638
Element Category: transition metal
Group, Period, Block: 5, 5, d
Color: silvery-white/ gray metalli
Other Names: Niob, Niobio, Nióbio, Niobio
Melting Point: 2477 °C, 4491 °F, 2750 K
Boiling Point: 4744 °C, 8571 °F, 5017 K
Density: 8.57 g·cm3
Liquid Density @ Melting Point: N/A
Density @ 20°C: 8.57 g/cm3
Density of Solid: 8570 kg·m3
Specific Heat: 0.27 (kJ/kg K)
Superconductivity Temperature: 9.25 [or -263.9 °C (-443 °F)] K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 27.2
Heat of Vaporization (kJ·mol-1): 680.19
Heat of Atomization (kJ·mol-1): 722.819
Thermal Conductivity: 53.7 W·m-1·K-1
Thermal Expansion: 7.3 µm/(m·K)
Electrical Resistivity: (0 °C) 152 nΩ·m
Tensile Strength: N/A
Molar Heat Capacity: N/A
Young's Modulus: 105 GPa
Shear Modulus: 38 GPa
Bulk Modulus: 170 GPa
Poisson Ratio: 0.4
Mohs Hardness: 6
Vickers Hardness: 1320 MPa
Brinell Hardness: 736 MPa
Speed of Sound: (20 °C) 3480 m·s-1
Pauling Electronegativity: 1.6
Sanderson Electronegativity: 1.42
Allred Rochow Electronegativity: 1.23
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.4
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 41
Protons: 41
Neutrons: 52
Electron Configuration: [Kr] 4d4 5s1
Atomic Radius: 146 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 164±6 pm
Covalent Radius (Å): 1.56
Van der Waals Radius: 200 pm
Oxidation States: 5, 4, 3, 2, -1 (mildly acidic oxide)
Phase: Solid
Crystal Structure: cubic body-centered
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 88.381
1st Ionization Energy: 652.13 kJ·mol-1
2nd Ionization Energy: 1381.68 kJ·mol-1
3rd Ionization Energy: 2416.01 kJ·mol-1
CAS Number: 7440-03-1
EC Number: 231-113-5
MDL Number: MFCD00011126
Beilstein Number: N/A
SMILES Identifier: [Nb]
InChI Identifier: InChI=1S/Nb
PubChem CID: 23936
ChemSpider ID: 22378
Earth - Total: 800 ppb
Mercury - Total: 610 ppb
Venus - Total: 840 ppb 
Earth - Seawater (Oceans), ppb by weight: 0.001
Earth - Seawater (Oceans), ppb by atoms: 0.000067
Earth -  Crust (Crustal Rocks), ppb by weight: 17000
Earth -  Crust (Crustal Rocks), ppb by atoms: 3700
Sun - Total, ppb by weight: 4
Sun - Total, ppb by atoms: 0.05
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: 190
Meterorite (Carbonaceous), ppb by atoms: 30
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 2
Universe, ppb by atom: 0
Discovered By: Charles Hatchett
Discovery Date: 1801
First Isolation: N/A

Health, Safety & Transportation Information for Niobium

Some niobium compounds are considered toxic. Safety data for Niobium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Niobium.

Safety Data
Signal Word Danger
Hazard Statements H250
Hazard Codes F
Risk Codes 17
Safety Precautions 6
RTECS Number QT9900000
Transport Information UN 1383 4.2/PG 1
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)
Review and Print SDS for Niobium Metal


Date Created: 05/15/2015
Date Revised: 05/15/2015


Product Name: Niobium Metal

Product Number: All applicable American Elements product codes, e.g. NB-M-02, NB-M-03, NB-M-04, NB-M-05

CAS #: 7440-03-1

Relevant identified uses of the substance: Scientific research and development

Supplier details:
American Elements
1093 Broxton Ave. Suite 2000
Los Angeles, CA 90024
Tel: +1 310-208-0551
Fax: +1 310-208-0351

Emergency telephone number:
Domestic, North America +1 800-424-9300
International +1 703-527-3887


Classification of the substance or mixture
Classification according to Regulation (EC) No 1272/2008
The substance is not classified as hazardous to health or the environment according to the CLP regulation.
Classification according to Directive 67/548/EEC or Directive 1999/45/EC
Not applicable
Information concerning particular hazards for human and environment:
No information known.
Hazards not otherwise classified
No information known.
Label elements
Labelling according to Regulation (EC) No 1272/2008
Not applicable
Hazard pictograms
Not applicable
Signal word
Not applicable
Hazard statements
Not applicable
WHMIS classification
Not controlled
Classification system
HMIS ratings (scale 0-4)
(Hazardous Materials Identification System)

Health (acute effects) = 0
Flammability = 0
Physical Hazard = 0
Other hazards
Results of PBT and vPvB assessment
PBT: Not applicable.
vPvB: Not applicable.


Chemical characterization: Substances
CAS# Description:
7440-03-1 Niobium
Identification number(s):
EC number: 231-113-5


Description of first aid measures
General information
No special measures required.
After inhalation
Seek medical treatment in case of complaints.
After skin contact
Generally the product does not irritate the skin.
After eye contact
Rinse opened eye for several minutes under running water. If symptoms persist, consult a doctor.
After swallowing
If symptoms persist consult doctor.
Information for doctor
Most important symptoms and effects, both acute and delayed
No further relevant information available.
Indication of any immediate medical attention and special treatment needed
No further relevant information available.


Extinguishing media
Suitable extinguishing agents
Special powder for metal fires. Do not use water.
For safety reasons unsuitable extinguishing agents
Special hazards arising from the substance or mixture
If this product is involved in a fire, the following can be released:
Metal oxide fume
Advice for firefighters
Protective equipment:
No special measures required.


Personal precautions, protective equipment and emergency procedures
Not required.
Environmental precautions:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow product to reach sewage system or any water course.
Do not allow to penetrate the ground/soil.
Methods and material for containment and cleaning up:
Pick up mechanically.
Prevention of secondary hazards:
No special measures required.
Reference to other sections
See Section 7 for information on safe handling
See Section 8 for information on personal protection equipment.
See Section 13 for disposal information


Precautions for safe handling
Keep container tightly sealed.
Store in cool, dry place in tightly closed containers.
Information about protection against explosions and fires:
No special measures required.
Conditions for safe storage, including any incompatibilities
Requirements to be met by storerooms and receptacles:
No special requirements.
Information about storage in one common storage facility:
Do not store together with acids.
Store away from oxidizing agents.
Further information about storage conditions:
Keep container tightly sealed.
Store in cool, dry conditions in well sealed containers.
Specific end use(s)
No further relevant information available.


Additional information about design of technical systems:
No further data; see section 7.
Control parameters
Components with limit values that require monitoring at the workplace:
The product does not contain any relevant quantities of materials with critical values
that have to be monitored at the workplace.
Additional information: No data
Exposure controls
Personal protective equipment
General protective and hygienic measures
The usual precautionary measures for handling chemicals should be followed.
Maintain an ergonomically appropriate working environment.
Breathing equipment: Not required.
Protection of hands: Not required.
Penetration time of glove material (in minutes): Not determined
Eye protection: Safety glasses
Body protection: Protective work clothing.


Information on basic physical and chemical properties
General Information
Form: Solid in various forms
Color: Silver grey
Odor: Odorless
Odor threshold: Not determined.
pH-value: Not applicable.
Change in condition
Melting point/Melting range: 2477 °C (4491 °F)
Boiling point/Boiling range: 4927 °C (8901 °F)
Sublimation temperature / start: Not determined
Flammability (solid, gaseous): Not determined.
Ignition temperature: Not determined
Decomposition temperature: Not determined
Auto igniting: Not determined.
Danger of explosion: Not determined.
Explosion limits:
Lower: Not determined
Upper: Not determined
Vapor pressure: Not applicable.
Density at 20 °C (68 °F): 8.57 g/cm³ (71.517 lbs/gal)
Relative density: Not determined.
Vapor density: Not applicable.
Evaporation rate: Not applicable.
Solubility in / Miscibility with Water: Insoluble
Partition coefficient (n-octanol/water): Not determined.
dynamic: Not applicable.
kinematic: Not applicable.
Other information
No further relevant information available


No information known.
Chemical stability
Stable under recommended storage conditions.
Thermal decomposition / conditions to be avoided:
Decomposition will not occur if used and stored according to specifications.
Possibility of hazardous reactions
Reacts with strong oxidizing agents
Conditions to avoid
No further relevant information available.
Incompatible materials:
Oxidizing agents
Hazardous decomposition products:
Metal oxide fume


Information on toxicological effects
Acute toxicity: No effects known.
LD/LC50 values that are relevant for classification: No data
Skin irritation or corrosion: May cause irritation
Eye irritation or corrosion: May cause irritation
Sensitization: No sensitizing effects known.
Germ cell mutagenicity: No effects known.
No classification data on carcinogenic properties of this material is available from the EPA, IARC, NTP, OSHA or ACGIH.
Reproductive toxicity: No effects known.
Specific target organ system toxicity - repeated exposure: No effects known.
Specific target organ system toxicity - single exposure: No effects known.
Aspiration hazard: No effects known.
Subacute to chronic toxicity: No effects known.
Additional toxicological information:
To the best of our knowledge the acute and chronic toxicity of this substance is not fully known.


Aquatic toxicity:
No further relevant information available.
Persistence and degradability
No further relevant information available.
Bioaccumulative potential
No further relevant information available.
Mobility in soil
No further relevant information available.
Additional ecological information:
General notes:
Do not allow material to be released to the
environment without proper governmental permits.
Avoid transfer into the environment.
Results of PBT and vPvB assessment
PBT: Not applicable.
vPvB: Not applicable.
Other adverse effects
No further relevant information available.


Waste treatment methods
Consult state, local or national regulations to ensure proper disposal.
Uncleaned packagings:
Disposal must be made according to official regulations.


Not applicable
UN proper shipping name
Not applicable
Transport hazard class(es)
Not applicable
Packing group
Not applicable
Environmental hazards:
Not applicable.
Special precautions for user
Not applicable.
Transport in bulk according to Annex II of MARPOL73/78 and the IBC Code
Not applicable.
Transport/Additional information:
Marine Pollutant (DOT):
UN "Model Regulation":


Safety, health and environmental regulations/legislation specific for the substance or mixture
National regulations
All components of this product are listed in the U.S. Environmental Protection Agency Toxic Substances Control Act Chemical substance Inventory.
All components of this product are listed on the Canadian Domestic Substances List (DSL).
SARA Section 313 (specific toxic chemical listings)
Substance is not listed.
California Proposition 65
Prop 65 - Chemicals known to cause cancer
Substance is not listed.
Prop 65 - Developmental toxicity
Substance is not listed.
Prop 65 - Developmental toxicity, female
Substance is not listed.
Prop 65 - Developmental toxicity, male
Substance is not listed.
Information about limitation of use:
For use only by technically qualified individuals.
Other regulations, limitations and prohibitive regulations
Substance of Very High Concern (SVHC) according to the REACH Regulations (EC) No. 1907/2006.
Substance is not listed.
The conditions of restrictions according to Article 67 and Annex XVII of the Regulation (EC) No 1907/2006 (REACH) for the manufacturing, placing on the market and use must be observed.
Substance is not listed.
Annex XIV of the REACH Regulations (requiring Authorisation for use)
Substance is not listed.
REACH - Pre-registered substances
Substance is listed.
Chemical safety assessment:
A Chemical Safety Assessment has not been carried out.


Safety Data Sheet according to Regulation (EC) No. 1907/2006 (REACH). The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. American Elements shall not be held liable for any damage resulting from handling or from contact with the above product. See reverse side of invoice or packing slip for additional terms and conditions of sale. COPYRIGHT 1997-2016 AMERICAN ELEMENTS. LICENSED GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLY.

Niobium Isotopes

Niobium has one stable isotope: 93Nb

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
81Nb 80.94903(161)# <44 ns ß+ + p to 80Y; p to 80Zr; ß+ to 81Zr 3/2-# N/A 655.88 -
82Nb 81.94313(32)# 51(5) ms ß+ to 82Zr 0+ N/A 669.55 -
83Nb 82.93671(34) 4.1(3) s ß+ to 83Zr (5/2+) N/A 684.15 -
84Nb 83.93357(32)# 9.8(9) s ß+ to 84Zr; ß+ + p to 85Zr 3+ N/A 695.03 -
85Nb 84.92791(24) 20.9(7) s ß+ to 85Zr (9/2+) N/A 708.69 -
86Nb 85.92504(9) 88(1) s ß+ to 86Zr (6+) N/A 718.64 -
87Nb 86.92036(7) 3.75(9) min ß+ to 87Zr (1/2-) N/A 731.37 -
88Nb 87.91833(11) 14.55(6) min ß+ to 88Zr (8+) N/A 741.32 -
89Nb 88.913418(29) 2.03(7) h EC to 89Zr (9/2+) N/A 754.05 -
90Nb 89.911265(5) 14.60(5) h EC to 90Zr 8+ 4.961 763.99
91Nb 90.906996(4) 680(130) y EC to 91Zr 9/2+ N/A 776.73 -
92Nb 91.907194(3) 3.47(24)E+7 y EC to 92Zr; ß- to 92Mo (7)+ 6.114 783.88 -
93Nb 92.9063781(26) Observationally Stable - 9/2+ 6.1705 792.89 100
94Nb 93.9072839(26) 2.03(16)E+4 y ß- to 94Mo (6)+ N/A 800.04 -
95Nb 94.9068358(21) 34.991(6) d ß- to 95Mo 9/2+ 6.141 809.05 -
96Nb 95.908101(4) 23.35(5) h ß- to 96Mo 6+ 4.976 815.26 -
97Nb 96.9080986(27) 72.1(7) min ß- to 97Mo 9/2+ 6.15 823.34 -
98Nb 97.910328(6) 2.86(6) s ß- to 98Mo 1+ N/A 829.56 -
99Nb 98.911618(14) 15.0(2) s ß- to 99Mo 9/2+ N/A 836.7 -
100Nb 99.914182(28) 1.5(2) s ß- to 100Mo 1+ N/A 841.99 -
101Nb 100.915252(20) 7.1(3) s ß- to 101Mo (5/2#)+ N/A 853.79 -
102Nb 101.91804(4) 1.3(2) s ß- to 102Mo 1+ N/A 861.87 -
103Nb 102.91914(7) 1.5(2) s ß- to 103Mo (5/2+) N/A 869.95 -
104Nb 103.92246(11) 4.9(3) s ß- to 104Mo; ß- to 103Mo (1+) N/A 868.71 -
105Nb 104.92394(11) 2.95(6) s ß- to 105Mo; ß- to 104Mo (5/2+)# N/A 876.79 -
106Nb 105.92797(21)# 920(40) ms ß- to 106Mo; ß- to 105Mo 2+# N/A 884.87 -
107Nb 106.93031(43)# 300(9) ms ß- to 107Mo; ß- to 106Mo 5/2+# N/A 883.63 -
108Nb 107.93484(32)# 0.193(17) s ß- to 108Mo; ß- to 107Mo (2+) N/A 891.71 -
109Nb 108.93763(54)# 190(30) ms ß- to 109Mo; ß- to 108Mo 5/2+# N/A 899.79 -
110Nb 109.94244(54)# 170(20) ms ß- to 110Mo; ß- to 109Mo 2+# N/A 898.55 -
111Nb 110.94565(54)# 80# ms [>300 ns] Unknown 5/2+# N/A 906.63 -
112Nb 111.95083(75)# 60# ms [>300 ns] Unknown 2+# N/A 905.39 -
113Nb 112.95470(86)# 30# ms [>300 ns] Unknown 5/2+# N/A 913.47 -