Mn
Co
26Fe55.845
Wikimedia Commons
Deep beneath our feet lies Earth's molten heart. It is almost entirely made of iron. This metal generates the planet's magnetic field, shielding us from deadly cosmic radiation. Without iron at the core, life on Earth would never have survived.
But iron matters far beyond geology. Every red blood cell carries hemoglobin — a protein built around iron atoms. It grabs oxygen in your lungs and delivers it to every cell. Each breath you take works because of iron. And from this same metal we make steel — the backbone of modern civilization.
Humans have used iron for over 3,000 years. The Iron Age transformed warfare, farming, and construction. Today, iron alloys account for about 90% of all metal produced worldwide. Steel and cast iron are everywhere: in skyscrapers, bridges, ships, and cars.
The world produces over 1.8 billion tons of steel each year. China, India, and Japan lead production. Iron ore reserves are massive — Australia, Brazil, and Ukraine hold some of the largest deposits on the planet.
26
Atomic Number
55.845u
Atomic Mass
[Ar] 3d6 4s2
e-config
1.83
Electroneg.
ironwhat is ironiron propertiesiron usesiron elementFe
Properties
Physical Properties
1811 K
1538°C
Melting point
3134 K
2861°C
Boiling point
7.87
g/cm³
Density
1.83
Pauling
Electronegativity
Atomic Structure
Group
8
Period
4
Block
D
Electron configuration
[Ar] 3d6 4s2
Bohr Model
K=2L=8M=14N=2
Extended Properties
Structure
Crystal Structure
body-centered cubic (α-Fe)
Magnetic Ordering
ferromagnetic
Mohs Hardness
4
Bulk Modulus
170GPa
Shear Modulus
82GPa
Poisson Ratio
0.29
Brinell Hardness
490MPa
Vickers Hardness
608MPa
Physical Properties
Thermal Conductivity
80.4W/(m·K)
Electrical Resistivity
96.1nΩ·m
Speed of Sound
5120m/s
Young's Modulus
211GPa
Specific Heat
0.449J/(g·K)
Heat of Fusion
13.81kJ/mol
Heat of Vaporization
340kJ/mol
Electron Affinity
15.7kJ/mol
Molar Volume
7.09cm³/mol
Atomic Properties
Atomic Radius
126pm
Covalent Radius
132pm
Van der Waals Radius
156pm
First Ionization Energy
762.5kJ/mol
Abundance
Earth Abundance
5.0%
Universe Abundance
0.11%
Ocean Abundance
0.0000030%
Human Body
0.006%
General
Atomic number26
Atomic mass55.8450u
Group8
Period4
BlockD
Standard stateSolid
Physical properties
Density7.874g/cm³
Melting point1811.00 K (1538°C)
Boiling point3134.00 K (2861°C)
Speed of sound5120m/s
Young's modulus211GPa
Mohs hardness4
Molar volume7.09cm³/mol
Bulk modulus170GPa
Shear modulus82GPa
Poisson ratio0.29
Brinell hardness490MPa
Vickers hardness608MPa
Thermal properties
Thermal conductivity80.4W/(m·K)
Specific heat0.449J/(g·K)
Heat of fusion13.81kJ/mol
Heat of vaporization340kJ/mol
Atomic properties
Electron configuration[Ar] 3d6 4s2
Electronegativity1.83Pauling
Atomic radius126pm
Covalent radius132pm
Van der Waals radius156pm
Electromagnetic
First ionization energy762.5kJ/mol
Electron affinity15.7kJ/mol
Electrical resistivity96.1nΩ·m
Crystal structurebody-centered cubic (α-Fe)
Magnetic orderingferromagnetic
Abundance
Earth abundance5.0%
Universe abundance0.11%
Ocean abundance0.0000030%
Human body abundance0.006%
Numbers & Comparisons
32%
of Earth's mass
Iron is the most abundant element on our planet by mass. There is more iron than oxygen or silicon
1,538 °C
melting point
Ten times hotter than a kitchen oven. Yet for industry it is ideal — iron melts far more easily than tungsten
5,120 m/s
speed of sound
Sound travels through iron 15 times faster than through air (343 m/s)
1.8 B tons
steel per year
That is how much steel humanity produces annually. It equals the weight of 250 Great Pyramids
Applications
🏗️
Construction: steel rebar and beams hold up skyscrapers, bridges, and tunnels — modern cities could not exist without them
🔩
Transportation: car bodies, railway tracks, and ship hulls are all made of steel — an alloy built on iron
⚡
Energy: transformer and generator cores use iron because it conducts magnetic fields exceptionally well
🩺
Medicine: iron in hemoglobin carries oxygen through the blood; iron supplements treat anemia in millions of people
🔩
Machinery: engines, lathes, and bearings rely on cast iron and steel to withstand pressure, friction, and high heat
🔬
Household: cast-iron skillets, knives, nails, and keys — the most ordinary objects around us are made from iron alloys
🌱
Chemical industry: iron catalysts speed up ammonia synthesis (the Haber process) to produce fertilizers that feed the world
🚀
Space science: iron-nickel meteorites that fall to Earth are samples of matter from the early Solar System
Where to find in everyday life
Cast-iron skillet
Cast iron is iron plus carbon. It holds heat evenly and lasts for decades
Nails and screws
Most fasteners in your home are steel. Without iron you could not even hang a shelf
Knives and scissors
Blades are made from hardened steel — an alloy of iron with chromium and carbon
Heating radiator
Cast-iron and steel radiators warm homes. Iron transfers heat efficiently into the room
Fridge magnet
Magnets cling to the door because the fridge body is steel — and steel contains iron
Safety & Warnings
Metallic iron is safe to touch and non-toxic. However, fine iron dust is flammable and can explode in enclosed spaces. Rust (iron oxide) itself is harmless, but rusty surfaces often harbor bacteria, including the tetanus pathogen. Excess iron in the body (hemochromatosis) can damage the liver and heart. The recommended daily intake for adults is 8–18 mg.
Dangerous
Fun Facts
Earth's core is about 85% iron. It forms a molten ball 2,440 km across — nearly the size of Mars.
An adult body contains 3–4 grams of iron. Enough for one small nail. But without it, blood could not carry oxygen.
Iron is the last element forged inside living stars. To create anything heavier, a star must explode as a supernova.
Ancient Egyptians called iron 'metal from the sky.' The earliest iron tools were hammered from meteorites, long before smelting was invented.
Only three metals can be permanently magnetized: iron, cobalt, and nickel. That's why magnets stick to your fridge door.
The world produces over 1.8 billion tons of steel every year. That's more than 90% of all metal made by humans.