de en fr hr it es
Neighborhood
 
 
 
Mn
25
Fe
26
Co
27
Tc
43
Ru
44
Rh
45

 

Periodic table

de  German

Eisen

en  English

Iron

fr  French

Fer

hr  Croatian

Željezo

it  Italian

Ferro

es  Spanish

Hierro

 

Fe
Fe
Ferrum

PERIODIC TABLE OF THE ELEMENTS

IRON

TRANSITION ELEMENT: IRON GROUP

 

Atomic number:26

Group numbers:8

Period:4

Electronic configuration:[Ar] 3d6 4s2

Formal oxidation number:+2 +3

Electronegativities:1.83

Atomic radius / pm:124.1

Relative atomic mass:55.845 ± 0.002

 

Iron has been known since ancient times. The origin of the name comes from the Latin word ferrum meaning iron. It is a malleable, ferromagnetic, ductile, silvery-white metal. Exposed surfaces form red-brown oxides. Iron forms very strong alloys (steel). Iron dust flammable. It's the Fourth most abundant element in the earth's crust. Iron is obtained from iron ores. Pure metal is produced in blast furnaces by layering limestone, coke and iron ore and forcing hot gasses into the bottom. This heats the coke red hot and the iron is reduced from its oxides and liquefied where it flows to the bottom. Iron is the most common metal in human society. More than 90% of all metal refined in the world is iron. It is used in steel and other alloys. Iron is the chief constituent of hemoglobin which carries oxygen in blood vessels. It's oxides are used in magnetic tapes and disks.

PHYSICAL PROPERTIES

Density / g dm-3:7874 (293 K)

 7035 (m.p.)

Molar volume / cm3mol-1:7.09 (293 K)

 7.94 (m.p.)

Electrical resistivity / μΩcm:9.71 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m-1K-1:80.2

Melting point / °C:1538

Boiling point / °C:2861

Heat of fusion / kJ mol-1:14.9

Heat of vaporization / kJ mol-1:340.2

Heat of atomization / kJ mol-1:413.96

IONIZATION ENERGIES

First ionization energy / kJ mol-1:762.47

Second ionization energy / kJ mol-1:1561.90

Third ionization energy / kJ mol-1:2957.49

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:70700

in the oceans / ppm:0.01

CRYSTALLOGRAPHIC DATA

body-centered cubic

Crystal structure:

body-centered cubic

Unit-cell dimensions / pm:

a=286.645

Space group:

Im3m

ISOTOPES

IsotopeRelative atomic massMass percent (%)
54Fe53.939615(1)5.8(1)
56Fe55.934942(1)91.72(30)
57Fe56.935399(1)2.1(1)
58Fe57.933280(1)0.28(1)

REDUCTION POTENTIALS

Balanced half-reaction Eo / V
Fe3+ + 3e- = Fe(s)- 0.04
Fe3+ + e- = Fe2++0.771
Fe3+ + e- = Fe2++0.700 (1 mol dm-3 HCl)
Fe3+ + e- = Fe2++0.732 (1 mol dm-3 HClO4)
Fe3+ + e- = Fe2++0.68 (1 mol dm-3 H2SO4)
Fe2+ + 2e- = Fe(s)- 0.440
FeOH2+ + H+ + e- = Fe2+ + H2O+0.91
Fe(OH)2+ + 2H+ + e- = Fe2+ + 2H2O+1.19
FeO42- + 8H+ + 3e- = Fe3+ + 4H2O+1.70
FeO42- + 7H+ + 3e- = FeOH2+ + 3H2O+1.65
FeO42- + 6H+ + 3e- = Fe(OH)2+ + 2H2O+1.56
FeO42- + 5H+ + 3e- = HFeO2 + 2H2O+1.00
HFeO2- + 3H+ + 2e- = Fe(s) + 2H2O+0.49
Fe(CN)63- + e- = Fe(CN)64-+0.36
Fe(CN)63- + e- = Fe(CN)64-+0.71 (1 mol dm-3 HCl)
Fe(CN)63- + e- = Fe(CN)64-+0.72 (1 mol dm-3 HClO4)
Fe(CN)63- + e- = Fe(CN)64-+0.72 (1 mol dm-3 H2SO4)
Fe(C12H8N2)33+ + e- = Fe(C12H8N2)32++1.06

 

25 Manganese <=
26 Iron
=> 27 Cobalt