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Element 44 - Ruthenium (Ru)
From
Ruthenia
, Latin for Russia; discovered 1844. Pure ruthenium is too hard and brittle to machine. It makes a top-notch "hardener," however, when it is alloyed with platinum. But used in excess of 15 percent, ruthenium is ruinous, making the metals too hard to be worked.
Properties
Atomic Number
:
44
Atomic Weight
:
101.07
Electron Configuration
(at ground state):
1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
4s
2
4p
6
4d
7
5s
1
Oxidation States
(Bold most stable):
+2,
+3
,
+4
, +6, +8
Boiling Point
(K):
4425
Melting Point (K):
2610
Density
(at 300K -- g/cm
3
):
12.37
Atomic Volume (at 300K -- cm
3
/mol)
8.30
Number of stable
isotopes
:
7
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
106 -- 267 days --
beta particle
(
electron
) emission
Covalent Radius (Å):
1.25
Atomic Radius (Å):
1.34
First
Ionization Potential
(V):
7.37
Electronegativity
(Pauling's):
2.2
Specific Heat
Capacity (at 300K -- J g
-1
K
-1
):
0.238
Heat of Vaporization (kJ/mol):
567.77
Heat of Fusion (kJ/mol):
25.52
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
14.9
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
117
Crystal Structure:
Hexagonal
Acid
-
Base
Properties:
Slightly acidic