Iridium

Chemical, physical and material properties and data of the chemical element Iridium.

Content

General data

Atomar properties

Electron configutation

General Information about Iridium

Regular nameIridiumChemical symbolIrOther namesSystematic nameHistorical namesName meaning, originDiscovery (year)OccurencePosition in the PSEGroup membership

Atomar Properties of Iridium

Atomic number Z77 = number of protonsStandard Atomic Weight192.217 (2)

Electron configuration of Iridium

1s	2s	2p	3s	3p	3d	4s	4p	4d	4f	5s	5p	5d	5f	6s	6p	6d	6f	7s	7p
2	2	6	2	6	10	2	6	10	14	2	6	7		2

Abbreviated form: [Xe] 4f¹⁴ 5d⁷ 6s² .

Ionization Energies of Iridium

The following table lists the ionization energies IE (ionization potentials); the IE is the energy required in electron volts (eV) per atom to separate a given electron from an Iridium atom.

IE1
8.96702

Isotopic Data of Iridium

An overview of the nuclides as well as the isotopic data and properties are listed on the following page: Iridium isotopes.

Chemistry of Iridium

Oxidation states+3. +4Electronegativity2.2 (Pauling original)
2.20 (Pauling)
1.68 (Allen)
5.4 eV (Pearson)Electron affinity1.564 36(15) eV
150.94(2) kJ mol^-1

Standard Electrode Potential

E⁰ (V)	Symbol	N_ox	Name Ox. Name Red.	Ox. Red.	e^-
0.223	Ir	+ IV + III	Iridium dioxide Iridium(III) cation	IrO₂ + 4 H⁺ ⇄ Ir³⁺ + 2 H₂O	+ e^-
0.49	Ir	+ IV + III	Hexaiodoiridium(IV) Hexaiodoiridium(III)	IrI₆^2- ⇄ IrI₆^3-	+ e^-
0.77	Ir	+ III 0	Hexachloroiridium(III) Iridium	IrI₆^3- ⇄ Ir + 6 Cl^-	+ 3 e^-
0.805	Ir	+ IV + III	Hexabromoiridium(IV) Hexabromoiridium(III)	IrBr₆^2- ⇄ IrBr₆^3-	+ e^-
0.835	Ir	+ IV 0	Hexachloroiridium(IV) Iridium	IrCl₆^2- ⇄ Ir + 6 Cl^-	+ 4 e^-
0.867	Ir	+ IV + III	Hexachloroiridium(IV) Hexachloroiridium(III)	IrCl₆^2- ⇄ IrCl₆^3-	+ e^-
1.156	Ir	+ III 0	Iridium(III) cation Iridium	Ir³⁺ + 2 H₂O ⇄ Ir	+ 3 e^-

Material and Physical Properties

Melting point2446 °CEnthalpy of fusion (molar)41.12 kJ mol^-1Boiling point4428 °CEnthalpy of vaporization563.6 kJ mol^-1Density22.65 g cm^-3

External Data, Identifiers

CAS registry number7439-88-5InChI =1S/IrInChIKeyGKOZUEZYRPOHIO-UHFFFAOYSA-NPubChem ID23924

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Last update: 2022-12-12

Perma link: https://www.chemlin.org/chemical-elements/iridium.php