Periodic Table

Iron

Transition Metal

Quick Facts about Iron

Mn
  • solid- state of matter at room temperature
  • Stable- has at least one stable isotope
  • +3, +2- common oxidation states in compounds
  • BCC- crystal structure, atomic arrangement in solid form
Co

Iron (Fe) is element 26 on the periodic table. Atomic mass of Fe: 55.8450 u. Fe is in period 4, group 8. Melting point of Fe: 1811.00 K.Density of Fe: 7.87 g/cm³.

Why Iron Matters

The element that built civilization—from ancient swords to modern skyscrapers

In Your Home

  • Cast iron pans and steel cookware
  • Nails, screws, and structural beams
  • Cars, appliances, and tools
  • Iron supplements and fortified cereals

Industry Uses

ConstructionSteel reinforces concrete in every modern building
AutomotiveAverage car contains 900 kg of steel
ShippingSteel cargo ships and containers move global trade
EnergySteel pipelines transport oil and natural gas

In Your Body

✓ Essential for life

Central atom in hemoglobin—carries oxygen in your blood. Essential for energy production in cells. Iron deficiency causes anemia. Your body contains about 4 grams of iron.

Safety: Iron overload (hemochromatosis) damages organs. Acute iron poisoning from supplements can be fatal, especially in children.

Discovery of Iron

Discovered by Known to the ancients.,

Name origin: Anglo-Saxon: iron; symbol from Latin: ferrum (iron).

History & Events

1200 BCE
Iron Age Begins
Iron smelting spread across the Middle East, replacing bronze and transforming warfare and agriculture
1856
Bessemer Process
Henry Bessemer invented mass steel production, enabling railroads and skyscrapers
1912
Titanic Sinks
Brittle iron rivets may have contributed to the Titanic's rapid sinking after hitting an iceberg

Why "Fe" for Iron?

FeFerrum(Latin)

The symbol Fe comes from "Ferrum," the Latin word for iron. The English name "Iron" derives from the Old English "īsern" and Proto-Germanic origins, possibly related to early Celtic words.

About Iron

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 Properties of Fe

Atomic Number of Fe
26
Atomic Mass of Fe
55.8450 u
Electron Configuration
[Ar] 3d6 4s2
Electronegativity
1.83
Block
d-block
Group
8
Period
4

Physical Properties of Fe

Phase (STP)
solid
Melting Point of Fe
1811.00 K
Boiling Point of Fe
3134.00 K
Density of Fe
7.8740 g/cm3

Thermal Properties

Heat of Fusion
13.80 kJ/mol
Heat of Vaporization
340.00 kJ/mol
Specific Heat
0.45 J/g·K
Molar Heat Capacity
25.10 J/mol·K
Thermal Conductivity
80.40 W/m·K

Atomic Radii

Calculated
140 pm
Covalent
116 pm
Van der Waals
204 pm
Metallic
117 pm

Common Misconceptions

Wrong:Spinach is high in iron (Popeye myth).
Correct:Spinach has moderate iron, but a decimal error in 1870 overstated it 10x. Also, spinach iron is poorly absorbed.
Wrong:Iron and steel are the same thing.
Correct:Steel is an alloy of iron with carbon (and other elements). Pure iron is softer and rusts more easily.
Wrong:Stainless steel won't rust.
Correct:Stainless steel resists rust due to chromium, but can still corrode in harsh conditions (salt, acids).

Isotopes of Iron

Iron has 4 naturally occurring isotopes, plus 3 notable radioactive isotopes.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
5226Fe (Fe-52)Iron-52 isotope51.9481140%8.3 hoursβ⁺, EC
5426Fe (Fe-54)Iron-54 isotope53.939608995.845%
5526Fe (Fe-55)Iron-55 isotope54.93829340%2.74 yearsEC
5626Fe (Fe-56)Iron-56 isotope55.9349363391.75%
5726Fe (Fe-57)Iron-57 isotope56.935392842.119%
5826Fe (Fe-58)Iron-58 isotope57.933274430.2820%
6026Fe (Fe-60)Iron-60 isotope59.9340720%2.6 million yearsβ⁻

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Isotope Applications

Isotopes of Iron have important real-world applications in science and industry.

Industrial Applications

55Fe is a beta emitting nuclide that serves as an electron source together with 63Ni (with a half-life of 99 years) in electron-capture detectors. Electron-capture detectors are used as thickness gauges or as detectors for organic analytes in gas chromatography [218].

Medical Applications

52Fe, with a half-life of 8.3 h, emits positrons and is used in positron emission tomography (PET) studies. It can be produced in a cyclotron from stable 50Cr by alpha particle capture [99], [219], [220].

Abundance

Earth's Crust
56.3 g/kg
Seawater
2.00 μg/kg

Uses

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

Geochemistry

Goldschmidt
siderophile
Geochemical Class
major

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