Iron

26
Fe
Group
8
Period
4
Block
d
Protons
Electrons
Neutrons
26
26
30
General Properties
Atomic Number
26
Atomic Weight
55.845
Mass Number
56
Category
Transition metals
Color
Gray
Radioactive
No
From the Latin word ferrum
Crystal Structure
Body Centered Cubic
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.
Electrons per shell
2, 8, 14, 2
Electron Configuration
[Ar] 3d6 4s2
Fe
The color of blood is due to the hemoglobin, an iron-containing protein
Physical Properties
Phase
Solid
Density
7.874 g/cm3
Melting Point
1811.15 K | 1538 °C | 2800.4 °F
Boiling Point
3134.15 K | 2861 °C | 5181.8 °F
Heat of Fusion
13.8 kJ/mol
Heat of Vaporization
347 kJ/mol
Specific Heat Capacity
0.449 J/g·K
Abundance in Earth's crust
6.3%
Abundance in Universe
0.11%
Pure
Image Credits: Wikimedia Commons (Alchemist-hp)
Pure iron chips, electrolytically refined, as well as a high purity iron cube for comparison
CAS Number
7439-89-6
PubChem CID Number
23925
Atomic Properties
Atomic Radius
126 pm
Covalent Radius
132 pm
Electronegativity
1.83 (Pauling scale)
Ionization Potential
7.9024 eV
Atomic Volume
7.1 cm3/mol
Thermal Conductivity
0.802 W/cm·K
Oxidation States
-2, -1, 1, 2, 3, 4, 5, 6, 7, 8
Applications
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.
Iron is considered to be non-toxic
Isotopes
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