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Element 42 - Molybdenum (Mo)
From
molybdos
, or lead--first found in what was thought to be lead ore; discovered 1778. Fifth highest melting metal, it is used in boiler plate, rifle barrels, and filaments. No vessel could be found in which to cast it until a special water-cooled crucible was devised in 1959.
Properties
Atomic Number
:
42
Atomic Weight
:
95.94
Electron Configuration
(at ground state):
1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
4s
2
4p
6
4d
5
5s
1
Oxidation States
(Bold most stable):
+2, +3, +4, +5,
+6
Boiling Point
(K):
4912
Melting Point (K):
2896
Density
(at 300K -- g/cm
3
):
10.22
Atomic Volume (at 300K -- cm
3
/mol)
9.40
Number of stable
isotopes
:
7
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
99 -- 66.02 hours --
beta particle
(
electron
) emission
Covalent Radius (Å):
1.30
Atomic Radius (Å):
1.39
First
Ionization Potential
(V):
7.099
Electronegativity
(Pauling's):
2.16
Specific Heat
Capacity (at 300K -- J g
-1
K
-1
):
0.25
Heat of Vaporization (kJ/mol):
590.4
Heat of Fusion (kJ/mol):
36
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
17.3
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
138
Crystal Structure:
Cubic, body centered
Acid
-
Base
Properties:
Very acidic