Niyobyo

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Niobium
41Nb
V

Nb

Ta
zirconiumniobiummolybdenum
Appearance
gray metallic, bluish when oxidized
A lump of gray shining crystals with hexagonal facetting
General properties
Name, simbolo, kaiphan niobium, Nb, 41
Pronunciation Plantilya:IPAc-en
Plantilya:Respell;
Plantilya:IPAc-en
Plantilya:Respell
Element category puthaw nga transisyon
Group, period, block 55, d
Standard atomic weight 92.90638
Electron configuration [Kr] 4d4 5s1
2, 8, 18, 12, 1
Electron shells of niobium (2, 8, 18, 12, 1)
History
Discovery Charles Hatchett (1801)
First isolation Christian Wilhelm Blomstrand (1864)
Recognized as a distinct element by Heinrich Rose (1844)
Physical properties
Phase magahi
Density (near r.t.) 8.57 g·cm−3
Melting point 2750 K, 2477 °C, 4491 °F
Boiling point 5017 K, 4744 °C, 8571 °F
Heat of fusion 30 kJ·mol−1
Heat of vaporization 689.9 kJ·mol−1
Molar heat capacity 24.60 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2942 3207 3524 3910 4393 5013
Atomic properties
Oxidation states 5, 4, 3, 2, -1
(mildly acidic oxide)
Electronegativity 1.6 (Pauling scale)
Ionization energies 1st: 652.1 kJ·mol−1
2nd: 1380 kJ·mol−1
3rd: 2416 kJ·mol−1
Atomic radius 146 pm
Covalent radius 164±6 pm
Miscellanea
Crystal structure cubic body-centered
Niobium has a cubic body-centered crystal structure
Magnetic ordering paramagnetic
Electrical resistivity (0 °C) 152 nΩ·m
Thermal conductivity 53.7 W·m−1·K−1
Thermal expansion 7.3 µm/(m·K)
Speed of sound (thin rod) (20 °C) 3480 m·s−1
Young's modulus 105 GPa
Shear modulus 38 GPa
Bulk modulus 170 GPa
Poisson ratio 0.40
Mohs hardness 6.0
Vickers hardness 1320 MPa
Brinell hardness 736 MPa
CAS registry number 7440-03-1
Most stable isotopes
Main article: Isotopes of niobium
iso NA half-life DM DE (MeV) DP
91Nb syn 6.8×102 y ε - 91Zr
91mNb syn 60.86 d IT 0.104e 91Nb
92Nb syn 10.15 d ε - 92Zr
γ 0.934 -
92Nb syn 3.47×107y ε - 92Zr
γ 0.561, 0.934 -
93Nb 100% 93Nb is stable with 52 neutrons
93mNb syn 16.13 y IT 0.031e 93Nb
94Nb syn 2.03×104 y β 0.471 94Mo
γ 0.702, 0.871 -
95Nb syn 34.991 d β 0.159 95Mo
γ 0.765 -
95mNb syn 3.61 d IT 0.235 95Nb
t  h  u
· r

Ang niyobyo (Iningles niobium) mao ang elementong kimiko sa talaang peryodiko nga may simbolo nga Nb ug kaiphan nga atomik 41. Ang niyobyo mao ang puthaw nga transisyon.

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