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Element 41 - Niobium (Nb)
From Niobe, daughter of the mythical Greek king Tantalus (niobium is found with tantalum); discovered 1801. Used in steel, atomic reactors, jet engines and rockets, it was known until 1950 as columbium, from Columbia--a poetic name for America, where its ore was first discovered.
Properties
Atomic Number
:
41
Atomic Weight
:
92.9064
Electron Configuration
(at ground state):
1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
4s
2
4p
6
4d
4
5s
1
Oxidation States
(Bold most stable):
+3,
+5
Boiling Point
(K):
5015
Melting Point (K):
2742
Density
(at 300K -- g/cm
3
):
8.57
Atomic Volume (at 300K -- cm
3
/mol)
10.80
Number of stable
isotopes
:
1
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
94 -- 2.0 x 10
4
years --
beta particle
(
electron
) emission
95 -- 35.15 days --
beta particle
(
electron
) emission
Covalent Radius (Å):
1.34
Atomic Radius (Å):
1.46
First
Ionization Potential
(V):
6.88
Electronegativity
(Pauling's):
1.6
Specific Heat
Capacity (at 300K -- J g
-1
K
-1
):
0.265
Heat of Vaporization (kJ/mol):
690.1
Heat of Fusion (kJ/mol):
26.9
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
6.6
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
53.7
Crystal Structure:
Cubic, body centered
Acid
-
Base
Properties:
Slightly acidic