Chemicool

Nb

41

92.9064
Niobium
General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles

General
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

States
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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Energies
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

Reactions
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

Radius
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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Conductivity
thermal conductivity 53.7 J/m-sec-deg electrical conductivity 80 1/mohm-cm
polarizability 15.7 A^3

Abundance
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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