Chemicool
Ir
77
192.22
Iridium
General
|
States
|
Energies
|
Oxidation & Electrons
|
Appearance & Characteristics
Reactions
|
Other Forms
|
Radius
|
Conductivity
|
Abundance
Encyclopedia Britannica articles
General
Name
Iridium
Symbol
Ir
atomic number
77
Atomic weight
192.22
Density @ 293 K
22.42 g/cm3
Atomic volume
8.54 cm3/mol
Group
Trans. Met.
discovered
1804
States
state (s, l, g)
s
melting point
2683.2 K
boiling point
4823 K
Heat of fusion
26.10 kJ/mol
Heat of vaporization
604.0 kJ/mol
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Energies
1st ionization energy
880 kJ/mole
electronegativity
2.2
2nd ionization energy
kJ/mole
electron affinity
151 kJ/mole
3rd ionization energy
kJ/mole
Specific heat
0.130 J/gK
heat atomization
665 kJ/mole atoms
Oxidation & Electrons
Shells
2,8,18,32,15,2
electron configuration
[Xe] 4f14 5d7 6s2
minimum oxidation number
-1
maximum oxidation number
6
min. common oxidation no.
0
max. common oxidation no.
4
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Appearance & Characteristics
structure
fcc: face-centered cubic
color
white
uses
Pt/Ir sparkplugs
toxicity
hardness
6.25 mohs
characteristics
hard, densest el, inert
Reactions
reaction with air
none
reaction with 6M HCl
none
reaction with 6M HCl
none
reaction with 15M HNO3
none
reaction with 6M NaOH
none
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Other Forms
number of isotopes
2
hydride(s)
none
oxide(s)
IrO2
chloride(s)
IrCl3
Radius
ionic radius (2- ion)
pm
ionic radius (1- ion)
pm
atomic radius
136 pm
ionic radius (1+ ion)
pm
ionic radius (2+ ion)
pm
ionic radius (3+ ion)
82 pm
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Conductivity
thermal conductivity
147 J/m-sec-deg
electrical conductivity
188.679 1/mohm-cm
polarizability
7.6 A^3
Abundance
source
nickel ores (sulfides)
rel. abund. solar system
-0.180 log
abundance earth's crust
-3 log
cost, pure
4200 $/100g
cost, bulk
$/100g
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