Iron

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

Content

General data

Atomar properties

Electron configutation

General Information about Iron

Regular nameIronChemical symbolFeOther namesSystematic nameHistorical namesName meaning, originDiscovery (year)OccurencePosition in the PSEGroup membership

Atomar Properties of Iron

Atomic number Z26 = number of protonsStandard Atomic Weight55.845 (2)

Electron configuration of Iron

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	6	2

Abbreviated form: [Ar] 3d⁶ 4s² .

Ionization Energies of Iron

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 Iron atom.

IE1	IE2	IE3	IE4	IE5	IE6	IE7	IE8
7.9024	16.1877	30.652	54.8	75.0	99.1	124.98	151.06

Isotopic Data of Iron

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

Chemistry of Iron

Oxidation states+2. +3. +6Electronegativity1.8 (Pauling original)
1.83 (Pauling)
1.80 (Allen)
3.5836 eV (Gosh Gupta)
4.06 eV (Pearson)Electron affinity0.153 236(34) eV
14.785(4) kJ mol^-1

Standard Electrode Potential

E⁰ (V)	Symbol	N_ox	Name Ox. Name Red.	Ox. Red.	e^-
-1.16	Fe	+ II 0	Hexacyanoferrate(II) anion Iron	[Fe(CN)₆]^4- + 6 H⁺ ⇄ Fe (s) + 4 HCN (g)	+ 2 e^-
-0.89	Fe	+ II 0	Iron(II) hydroxide Iron	Fe(OH)₂ (s) ⇄ Fe (s) + 2 OH^-	+ 2 e^-
-0.86	Fe	+ III + II	Iron(III) oxide Iron(II) hydroxide	Fe₂O₃ (s) + 3 H₂O ⇄ 2 Fe(OH)₂ (s) + 2 OH^-	+ 2 e^-
-0.44	Fe	+ II 0	Iron(II) cation Iron	Fe²⁺ ⇄ Fe (s)	+ 2 e^-
-0.04	Fe	+ III 0	Iron(III) cation Iron	Fe³⁺ ⇄ Fe (s)	+ 3 e^-
0.085	Fe	+II/+III 0	Iron(II,III) oxide Iron	Fe^II(Fe^III)₂O₄ + 8 H⁺ ⇄ 3 Fe (s) + 4 H₂O	+ 8 e^-
0.36	Fe	+ III + II	Hexacyanoferrate(III) anion Hexacyanoferrate(II) anion	[Fe(CN)₆]^3- ⇄ [Fe(CN)₆]^4-	+ e^-
0.77	Fe	+ III + II	Iron(III) cation Iron(II) cation	Fe³⁺ ⇄ Fe²⁺	+ e^-
0.81	Fe	+ VI + III	Ferrate anion Iron(III) oxide	2 FeO₄^2- + 5 H₂O ⇄ Fe₂O₃ (s) + 10 OH^- (aq)	+ 6 e^-
2.2	Fe	+ VI + III	Ferrate(VI) anion Iron(III) cation	FeO₄^2- + 8 H⁺ ⇄ Fe³⁺ + 4 H₂O	+ 3 e^-

Material and Physical Properties

Melting point1538 °CEnthalpy of fusion (molar)13.81 kJ mol^-1Enthalpy of fusion (specific)268 kJ mol^-1Boiling point2861 °CEnthalpy of vaporization351 kJ mol^-1Density7.874 g cm^-3

External Data, Identifiers

CAS registry number7439-89-6InChI =1S/FeInChIKeyXEEYBQQBJWHFJM-UHFFFAOYSA-NPubChem ID23925

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Last update: 2022-12-12

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