Template:Infobox iron

Iron,  ₂₆Fe

Spectral lines of iron
General properties
Name, symbol	iron, Fe
Appearance	lustrous metallic with a grayish tinge
Pronunciation	/ˈaɪ.ərn/ EYE-urn
Iron in the periodic table
– ↑ Fe ↓ Ru manganese ← iron → cobalt
Atomic number (Z)	26
Group, block	group 8, d-block
Period	period 4
Element category	transition metal
Standard atomic weight (±) (Ar)	55.845(2)
Electron configuration	[Ar] 3d6 4s2
per shell	2, 8, 14, 2
Physical properties
Phase	solid
Melting point	1811 K ​(1538 °C, ​2800 °F)
Boiling point	3134 K ​(2862 °C, ​5182 °F)
Density near r.t.	7.874 g/cm3
when liquid, at m.p.	6.98 g/cm3
Heat of fusion	13.81 kJ/mol
Heat of vaporization	340 kJ/mol
Molar heat capacity	25.10 J/(mol·K)
vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1728 1890 2091 2346 2679 3132
Atomic properties
Oxidation states	−4, −2, −1, +1, +2, +3, +4, +5, +6 ​(an amphoteric oxide)
Electronegativity	Pauling scale: 1.83
Ionization energies	1st: 762.5 kJ/mol 2nd: 1561.9 kJ/mol 3rd: 2957 kJ/mol (more)
Atomic radius	empirical: 126 pm
Covalent radius	Low spin: 132±3 pm High spin: 152±6 pm
Miscellanea
Crystal structure	​body-centered cubic (bcc) a=286.65 pm
Crystal structure	​face-centered cubic (fcc) between 1185–1667 K
Speed of sound thin rod	5120 m/s (at r.t.) (electrolytic)
Thermal expansion	11.8 µm/(m·K) (at 25 °C)
Thermal conductivity	80.4 W/(m·K)
Electrical resistivity	96.1 nΩ·m (at 20 °C)
Curie point	1043 K
Magnetic ordering	ferromagnetic
Young's modulus	211 GPa
Shear modulus	82 GPa
Bulk modulus	170 GPa
Poisson ratio	0.29
Mohs hardness	4
Vickers hardness	608 MPa
Brinell hardness	200–1180 MPa
CAS Number	7439-89-6
History
Discovery	before 5000 BC
Most stable isotopes of iron
iso NA half-life DM DE (MeV) DP 54Fe 5.8% >3.1×1022 y εε 0.668 54Cr 55Fe syn 2.73 y ε 0.231 55Mn 56Fe 91.72% 56Fe is stable with 30 neutrons 57Fe 2.2% 57Fe is stable with 31 neutrons 58Fe 0.28% 58Fe is stable with 32 neutrons 59Fe syn 44.503 d β− 1.565 59Co 60Fe syn 2.6×106 y β− 3.978 60Co
Decay modes in parentheses are predicted, but have not yet been observed

References

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