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Element 76 - Osmium (Os)
From
osme
, or odor; discovered 1804. A metal with a pungent smell, it is used to produce alloys of extreme hardnes.. Pen tips are 60 percent osmium. It is the densest metal known; a brick-sized chunk of osmium weighs about 56 pounds.
Properties
Atomic Number
:
76
Atomic Weight
:
190.2
Electron Configuration
(at ground state):
1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
4s
2
4p
6
4d
10
4f
14
5s
2
5p
6
5d
6
6s
2
Oxidation States
(Bold most stable):
+2, +3,
+4
, +6, +8
Boiling Point
(K):
5300
Melting Point (K):
3300
Density
(at 300K -- g/cm
3
):
22.6
Atomic Volume (at 300K -- cm
3
/mol)
8.43
Number of stable
isotopes
:
7
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
194 -- 6.0 years --
beta particle
(
electron
) emission
Covalent Radius (Å):
1.26
Atomic Radius (Å):
1.35
First
Ionization Potential
(V):
8.7
Electronegativity
(Pauling's):
2.2
Specific Heat
Capacity (at 300K -- J g
-1
K
-1
):
0.13
Heat of Vaporization (kJ/mol):
627.6
Heat of Fusion (kJ/mol):
29.29
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
12.3
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
87.6
Crystal Structure:
Hexagonal
Acid
-
Base
Properties:
Slightly acidic