Introduction
Group: 5 or VI B
Atomic Weight: 92.90638
Period: 5
CAS Number: 7440-03-1
Classification
No Stable Isotopes
Solid
Liquid
Gas
Solid (Predicted)
Description • Uses/Function
Discovered in 1801 by Hatchett in an ore sent to England more that a century before by John Winthrop the Younger, first governor of Connecticut. The metal was first prepared in 1864 by Blomstrand, who reduced the chloride by heating it ina hydrogen atmosphere. The name niobium was adopted by the International Union of Pure and Applied Chemistry in 1950 after 100 years ofcontroversy. Many leading chemical societies and government organizations refer to it by this name. Most metallurgists, leading metal societies, andall but one of the leading U.S. commercial producers, however, still refer to the metal as “columbium”. The element is found in niobite(or columbite),niobite-tantalite, pyrochlore, and euxenite. Large deposits of niobium have been found associated with carbonatites (carbon-silicate rocks), as aconstituent of pyrochlore. Extensive ore reserves are found in Canada, Brazil, Nigeria, Zaire, and in Russia. The metal can be isolated from tantalum,and prepared in several ways. It is a shiny, white, soft, and ductile metal, and takes on a bluish cast when exposed to air at room temperatures for along 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.It is used in arc-welding rods for stabilized grades of stainless steel. Thousands of pounds of niobium have been used in advance air frame systemssuch as were used in the Gemini space program. The element has superconductive properties; superconductive magnets have been made with Nb-Zrwire, which retains its superconductivity in strong magnetic fields. This type of application offers hope of direct large-scale generation of electricpower. Natural niobium is composed of only one isotope, 93Nb. Forty one other isotopes and isomers of niobium are now recognized. Niobium metal(99.9% pure) is priced at about $400/kg. 1
• "A number of transition metals (Ti, Zr, Hf, V, Nb, Ta, Mo, W) form interstitial carbides of composition MC and, in some cases, M2C. These carbides have extremely high melting points; they are very hard, and they are good electrical conductors." 2
Physical Properties
Melting Point:3* 2477 °C = 2750.15 K = 4490.6 °F
Electron Configuration: *[Kr] 5s1 4d4
n = 4
Electronegativity (Pauling scale):5 1.6
Specific Heat: 0.265 J/g°C 9 = 24.620 J/mol°C = 0.063 cal/g°C = 5.884 cal/mol°C
Earth - Source Compounds: oxides 15
External Links:
(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:20-4:21.
Boiling Point:3* 4744 °C = 5017.15 K = 8571.2 °F
Sublimation Point:3
Triple Point:3
Critical Point:3
Density:4 8.57 g/cm3
* - at 1 atm
Electron Configuration
Block: d
Highest Occupied Energy Level: 5
Valence Electrons:
Quantum Numbers:
ℓ = 2
mℓ = 1
ms = +½
Bonding
Electropositivity (Pauling scale): 2.4
Electron Affinity:6 0.893 eV
Oxidation States: +5,3
Work Function:7 4.20 eV = 6.7284E-19 J
Ionization Potential
eV 8
kJ/mol
1
6.75885
652.1
2
14.32
1381.7
Ionization Potential
eV 8
kJ/mol
3
25.04
2416.0
4
38.3
3695.4
Ionization Potential
eV 8
kJ/mol
5
50.55
4877.3
6
102.057
9847.0
7
125
12060.7
Thermochemistry
Thermal Conductivity: 53.7 (W/m)/K, 27°C 10
Heat of Fusion: 26.4 kJ/mol 11 = 284.2 J/g
Heat of Vaporization: 682 kJ/mol 12 = 7340.7 J/g
State of Matter
Enthalpy of Formation (ΔHf°)13
Entropy (S°)13
Gibbs Free Energy (ΔGf°)13
(kcal/mol)
(kJ/mol)
(cal/K)
(J/K)
(kcal/mol)
(kJ/mol)
(s)
0
0
8.70
36.4008
0
0
(g)
173.5
725.924
44.490
186.14616
162.8
681.1552
Isotopes
Nuclide
Mass 14
Half-Life 14
Nuclear Spin 14
Binding Energy
100Nb
99.914182(28)
1.5(2) s
1+
855.16 MeV
101Nb
100.915252(20)
7.1(3) s
(5/2#)+
866.96 MeV
102Nb
101.91804(4)
1.3(2) s
1+
875.03 MeV
103Nb
102.91914(7)
1.5(2) s
(5/2+)
883.10 MeV
104Nb
103.92246(11)
4.9(3) s
(1+)
881.86 MeV
105Nb
104.92394(11)
2.95(6) s
(5/2+)#
889.93 MeV
106Nb
105.92797(21)#
920(40) ms
2+#
898.00 MeV
107Nb
106.93031(43)#
300(9) ms
5/2+#
896.76 MeV
108Nb
107.93484(32)#
0.193(17) s
(2+)
904.83 MeV
109Nb
108.93763(54)#
190(30) ms
5/2+#
912.90 MeV
110Nb
109.94244(54)#
170(20) ms
2+#
911.66 MeV
111Nb
110.94565(54)#
80# ms [>300 ns]
5/2+#
919.73 MeV
112Nb
111.95083(75)#
60# ms [>300 ns]
2+#
918.48 MeV
113Nb
112.95470(86)#
30# ms [>300 ns]
5/2+#
926.56 MeV
81Nb
80.94903(161)#
<44 ns
3/2-#
669.21 MeV
82Nb
81.94313(32)#
51(5) ms
0+
682.87 MeV
83Nb
82.93671(34)
4.1(3) s
(5/2+)
697.46 MeV
84Nb
83.93357(32)#
9.8(9) s
3+
708.32 MeV
85Nb
84.92791(24)
20.9(7) s
(9/2+)
721.98 MeV
86Nb
85.92504(9)
88(1) s
(6+)
731.92 MeV
87Nb
86.92036(7)
3.75(9) min
(1/2-)
744.65 MeV
88Nb
87.91833(11)
14.55(6) min
(8+)
754.58 MeV
89Nb
88.913418(29)
2.03(7) h
(9/2+)
767.31 MeV
90Nb
89.911265(5)
14.60(5) h
8+
777.24 MeV
91Nb
90.906996(4)
680(130) a
9/2+
789.97 MeV
92Nb
91.907194(3)
3.47(24)E+7 a
(7)+
797.11 MeV
93Nb
92.9063781(26)
STABLE
9/2+
806.12 MeV
94Nb
93.9072839(26)
2.03(16)E+4 a
(6)+
813.26 MeV
95Nb
94.9068358(21)
34.991(6) d
9/2+
822.26 MeV
96Nb
95.908101(4)
23.35(5) h
6+
828.47 MeV
97Nb
96.9080986(27)
72.1(7) min
9/2+
836.54 MeV
98Nb
97.910328(6)
2.86(6) s
1+
842.75 MeV
99Nb
98.911618(14)
15.0(2) s
9/2+
849.89 MeV
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses. 14
Abundance
Earth - Seawater: 0.00001 mg/L 16
Earth -
Crust:
20 mg/kg = 0.002% 16
Earth -
Total:
800 ppb 17
Mercury -
Total:
610 ppb 17
Venus -
Total:
840 ppb 17
Chondrites - Total: 1.0 (relative to 106 atoms of Si) 18
Compounds
niobium(III) bromide
niobium(III) chloride
niobium(III) fluoride
niobium(III) iodide
niobium(III) nitride
niobium(IV) bromide
Safety Information
Material Safety Data Sheet - ACI Alloys, Inc.
For More Information
American Elements
Chemical & Engineering News
Chemical Elements
ChemGlobe
Chemicool
Environmental Chemistry
Sources
(2) - Jolly, William L. The Chemistry of the Non-Metals; Prentice-Hall: Englewood Cliffs, New Jersey, 1966; p 119.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(5) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(7) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(13) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(14) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(15) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(16) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(17) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(18) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.