General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles


Name Niobium Symbol Nb
atomic number 41 Atomic weight 92.9064
Density @ 293 K 8.57 g/cm3 Atomic volume 10.87 cm3/mol
Group Trans. Met. discovered 1801


state (s, l, g) s
melting point 2741.2 K boiling point 5031 K
Heat of fusion 26.40 kJ/mol Heat of vaporization 682.0 kJ/mol
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1st ionization energy 663.8 kJ/mole electronegativity 1.6
2nd ionization energy 1381.7 kJ/mole electron affinity 86.2 kJ/mole
3rd ionization energy 2416 kJ/mole Specific heat 0.26 J/gK
heat atomization 726 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,18,12,1 electron configuration [Kr] 4d4 5s1
minimum oxidation number -1 maximum oxidation number 5
min. common oxidation no. 0 max. common oxidation no. 5
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Appearance & Characteristics

structure bcc: body-centered cubic color silvery-white
uses stainless steels, magnets toxicity
hardness mohs characteristics soft


reaction with air none, w/ht = Nb2O3 reaction with 6M HCl none
reaction with 6M HCl none reaction with 15M HNO3
reaction with 6M NaOH none
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Other Forms

number of isotopes 1 hydride(s) NbH NbH2
oxide(s) NbO NbO2 Nb2O5 chloride(s) NbCl3 NbCl4 NbCl5


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 146 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) 86 pm
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thermal conductivity 53.7 J/m-sec-deg electrical conductivity 80 1/mohm-cm
polarizability 15.7 A^3


source columbite (oxide) rel. abund. solar system -0.156 log
abundance earth's crust 1.3 log cost, pure 18 $/100g
cost, bulk $/100g
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World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.