Iron

Iron (Fe)

Silvery malleable and ductile metallic transition element. Has nine isotopes and is the fourth most abundant element in the earth's crust. Required by living organisms as a trace element (used in hemoglobin in humans.) Quite reactive, oxidizes in moist air, displaces hydrogen from dilute acids and combines with nonmetallic elements.
Atomic Number26
Atomic Weight55.845
Mass Number56
Group8
Period4
Blockd
Protons26 p+
Neutrons30 n0
Electrons26 e-
Iron electrolytic and 1cm3 cube.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
140 pm
Atomic Volume
Covalent Radius
115.99999999999999 pm
Metallic Radius
117 pm
Ionic Radius
63 pm
Crystal Radius
77 pm
Van der Waals radius
204 pm
Density
7.87 g/cm³
Boiling Point
3,023 K
Melting Point
1,808 K
Electrons per shell2, 8, 14, 2
Electronegativity
1.83
Electrophilicity
1.0459042287068 eV/particle
Proton Affinity
754 kJ/mol
Electron Affinity
Ionization Potential
7.9024678 eV/particle
Heat of Vaporization
340 kJ/mol
Heat of Fusion
13.8 kJ/mol
Heat of Formation
415.5 kJ/mol
Molar Heat Capacity
Specific Heat Capacity
0.449 J/(g⋅K)
Thermal Conductivity
80.4 W/(m K)
Gas Basicity
731.1 kJ/mol
Dipole Polarizability
62 a₀
C6 Dispersion Coefficient
482 a₀
Oxidation States-2, -1, 1, 2, 3, 4, 5, 6, 7, 8
Color
Gray
Crystal StructureBody Centered Cubic (BCC)
Lattice Constant
2.87 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Ar] 3d6 4s2
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
Poisson Ratio
Shear Modulus
Young's Modulus
Allotropes
Alternate Names
Adiabatic Index
Appearance
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Electrical
Hardness
Magnetic Susceptibility
Magnetic
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
Classification
CategoryTransition metals, Transition metals
CAS GroupVIIIA
IUPAC GroupVIII
Glawe Number71
Mendeleev Number59
Pettifor Number61
Geochemical Classmajor
Goldschmidt Classsiderophile
Radioactivity
RadioactiveNo
Decay Mode
Half-Life
Lifetime
Abundance
Abundance in Earth's crust
56,300 mg/kg
Abundance in Oceans
0.002 mg/L
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe0.11%

Isotopes of Iron

Stable Isotopes
54Fe 56Fe 57Fe 58Fe
Unstable Isotopes
45Fe 46Fe 47Fe 48Fe 49Fe 50Fe 51Fe 52Fe 53Fe 55Fe 59Fe 60Fe 61Fe 62Fe 63Fe 64Fe 65Fe 66Fe 67Fe 68Fe 69Fe 70Fe 71Fe 72Fe

History

The first iron used by humans is likely to have come from meteorites. The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in about 4000 BC. The discovery of smelting around 3000 BC led to the start of the iron age around 1200 BC and the prominent use of iron for tools and weapons. From the Latin word ferrum

DiscoverersKnown to the ancients.
Discovery Location
Discovery Year
Name OriginAnglo-Saxon: iron; symbol from Latin: ferrum (iron).
Iron is considered to be non-toxic
The color of blood is due to the hemoglobin, an iron-containing protein

Uses

Iron is used to manufacture steel and other alloys important in construction and manufacturing. Iron is a vital constituent of plant and animal life and works as an oxygen carrier in hemoglobin. Iron oxide mixed with aluminum powder can be ignited to create a thermite reaction, used in welding and purifying ores. Used in steel and other alloys. Essential for humans. It is the chief constituent of hemoglobin which carries oxygen in blood vessels. Its oxides are used in magnetic tapes and disks.

Sources

Obtained from iron ores. Pure metal 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 liquified where it flows to the bottom