Niobium
| Latin name | Niobium |
| English name | Niobium |
| chemical symbol | Nb |
| atomic number | 41 |
| relative atomic mass | 92,90638 |
| period | 5 |
| group | V.B |
| classification | transition metals |
| discovery year | 1801 |
| discoverer | C. Hatchett |
| melting point [°C] | 2468 |
| boiling point [°C] | 4742 |
| density [g cm-3] | 8,57 |
| electronegativity [Pauling] | 1,6 |
| oxidation states | II, III, IV, V |
| electron configuration | [Kr]4d5 5s1 |
| atomic radius [pm] | 198 |
| covalent radius [pm] | 137 |
| specific heat [J g-1K-1] | 0,26 |
| heat of fusion [kJ mol-1] | 26,4 |
| thermal conductivity [W m-1 K-1] | 54 |
| el. conductivity [S m-1] | 6,7.106 |
| 1. ionizing potential [eV] | 6,7589 |
| 2. ionizing potential [eV] | 14,32 |
| 3. ionizing potential [eV] | 25,04 |
| Mohs hardness | 6 |
| Vickers hardness [MPa] | 1320 |
| Brinell hardness [MPa] | 736 |
| shear modulus [GPa] | 38 |
| Young's modulus [GPa] | 105 |
| point of superconductivity [K] | 9,25 |
| state at normal conditions | solid |
Niobium is a shiny, white, soft, and ductile metallic element.
Resources
- BARTHELMY, David. Mineral Species containing Niobium. In: Mineralogy database [online]. 2010 [cit. 2012-06-20]. Available from: http://webmineral.com/chem/Chem-Nb.shtml
- FAIRBROTHER, Fred. Chemistry of Niobium and Tantalum. Amsterdam: Elsevier, 1967.
- Niobium - Raw Materials and Processing. In: Tantalum-Niobium International Study Center [online]. 2011 [cit. 2013-03-03]. Available from: http://tanb.org/niobium
- PAPP, John. Niobium (Columbium). In: U.S. GEOLOGICAL SURVEY. Mineral Commodity Summaries [online]. 2013 [cit. 2013-02-28]. Available from: http://minerals.usgs.gov/.../mcs-2013-niobi.pdf
- STARÝ, Jaromír; SITENSKÝ, Ivo; HODKOVÁ, Tereza. Surovinové zdroje České republiky - Nerostné suroviny 2011. In: Česká geologická služba. Surovinové zdroje v ČR [online]. 2011 [cit. 2012-07-25]. Available from: http://www.geology.cz/.../rocenka2011sur.pdf
- SHAW, Richard; et al. Niobium-tantalum. Keyworth, Nottingham: British Geological Survey, 2011.
- STWERTKA, Albert. A Guide to the Elements. Oxford: University Press, 2002. ISBN 0-19-515027-9.
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