Symbol	Nb
Atomnummer	41
Gruppe	5 (Vanadiumgruppe)
Periode	5
Blok	d
Klassifikation	Overgangsmetal

Udseende	Gray metallic, bluish when oxidized
Farve	Grå

Antal protoner	41 p+
Antal neutroner	52 n0
Antal elektroner	41 e-

Fra Wikipedia, den gratis encyklopædiNiobium (opkaldt efter Tantalos' datter Niobe i den græske mytologi), tidligere kaldet niob, er det 41. grundstof i det periodiske system, og har det kemiske symbol Nb. Under normale temperatur- og trykforhold optræder dette overgangsmetal som et blødt, formbart og temmelig tungt gråligt metal.

Fase ved STP	Fast
Massefylde	8.57 g/cm3
Atommasse	92.9064 u

Smeltepunkt	2750 K 2476.85 °C 4490.33 °F
Kogepunkt	5017 K 4743.85 °C 8570.93 °F
Fordampningsvarme	690.1 kJ/mol

Elektronegativitet (Pauling Scale)	1.6
Elektronaffinitet	88.516 kJ/mol
Oxidationstrin	−3, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide)
Ioniseringsenergier	652.1 kJ/mol 1380 kJ/mol 2416 kJ/mol 3700 kJ/mol 4877 kJ/mol 9847 kJ/mol 12100 kJ/mol

Elektronkonfiguration Kortfattet konfiguration	[Kr] 4d4 5s1
Elektronkonfiguration Fuld konfiguration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d4 5s1
Elektronkonfigurationsdiagram	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d4 5s1
Elektroner pr. Skal	2, 8, 18, 12, 1
Valenselektroner	5
Valency-elektroner	3,5
Bohrs atommodel	Figur: Skaldiagram af Niobium (Nb) atom.
Orbital diagram	1s 2s 2p 3s 3p 3d 4s 4p 4d 5s

Opdaget	Charles Hatchett (1801)
Første isolation	Christian Wilhelm Blomstrand (1864)
Recognized as a distinct element by	Heinrich Rose (1844)
Opdagelse af niobium Niobium was identified by English chemist Charles Hatchett in 1801. He found a new element in a mineral sample that had been sent to England from Connecticut, United States in 1734 by John Winthrop F.R.S. (grandson of John Winthrop the Younger) and named the mineral columbite and the new element columbium after Columbia, the poetic name for the United States. In 1809, English chemist William Hyde Wollaston wrongly concluded that tantalum and columbium were identical. German chemist Heinrich Rose determined in 1846 that tantalum ores contain a second element, which he named niobium. In 1864 and 1865, a series of scientific findings clarified that niobium and columbium were the same element (as distinguished from tantalum), and for a century both names were used interchangeably. Niobium was officially adopted as the name of the element in 1949, but the name columbium remains in current use in metallurgy in the United States.

CAS Number	7440-03-1
ChemSpider ID	22378
EC number	231-113-5
PubChem CID Number	23936