Courses for Kids
Free study material
Offline Centres
Store Icon

Fe (Iron)

Reviewed by:
Last updated date: 21st Jul 2024
Total views: 289.8k
Views today: 7.89k
hightlight icon
highlight icon
highlight icon
share icon
copy icon

What is Fe (Iron)?

Fe is the symbol of the chemical element iron that has an atomic number 26. It is a metal that belongs to group 8 and is a part of the first transition series in the periodic table. It is one of the most common elements that is found in the earth's crust and accounts for 32.1% just right before oxygen which accounts for 30.1%. It forms most of the inner and other core of the earth and is considered the fourth common element of the earth’s crust. 

Iron in pure metallic form is very rare in the earth’s crust and could only be found in the form of the deposition of meteorites. But in contrast to it, iron is found in abundance in form of iron ore, the purification of which needs furnaces and kilns whose temperature needs to be higher up to 1,500 °C (2,730 °F) which is about  500 °C (900 °F) higher than the temperature required for smelting of copper. In Eurasia in about 2000 BCE, human beings mastered the technique of smelting iron and in about 1200 BCE the copper alloys were replaced by iron weapons in many of the regions. This time was considered as the transition period of the Bronze age to the Iron age. Steel, stainless steel, cast iron and special steel are the iron alloys that became far more common industrial elements in the modern age because of their suitable mechanical properties and low cost. 

Pure iron or pristine have a surface that is smooth and have a finish like a silvery-grey mirror. But iron has a tendency to readily reacts with oxygen and water to produce hydrated iron oxides that are browner to black in the finish that is commonly known as rust. Unlike many of the other metals that undergo oxidation to form passivating layers of oxides, iron oxides formed a larger volume than the metal itself and thus flake off exposing the fresh surface of the metal for further corrosion. Though iron readily reacts with the electrolytic iron, which is known as the pure form of iron has more resistance to corrosion. This topic mostly deals with the definition of Iron, its configuration and properties along with answering the questions like what are the uses of iron.


(Image Will be Updated Soon)

Electronic Configuration of Fe

Before starting with the electronic configuration of Fe we need to know the number of electrons that form the iron and the total number of electrons is 26. The configuration of the Fe ions becomes simple once we know the electronic configuration of Fe. All the 26 electrons will be set in particular orbits around the nucleus of the Fe atom. Therefore the first two electrons will go into 1s orbital. Since 1s orbital could hold only 2 electrons, therefore, the next two electrons will go in 2s orbitals. As the p subshell has the capacity to hold six electrons, therefore the next six electrons will go into the 2p subshell. Similarly, the next two electrons will go to 3s and the next six will go to 3p. Then we will shift to the 4s orbital rather than 3d as the energy of the s subshell is lower than d. Therefore it is easy for the electrons to occupy a subshell of higher orbit first. These two electrons are in 4s and the rest 6 electrons are in 3d. Therefore, the complete electronic configuration of iron will be as follows:-


Thus for Fe2+, we will remove the 2 electrons from the 4s subshell for a stable configuration. Therefore the electronic configuration for Fe2+ will be 1s22s22p63s23p63d6

Thus for Fe3+, we will remove the 3 electrons from the 4s subshell and 1 from the 3d subshell for a stable configuration. Therefore the electronic configuration for Fe2+ will be 1s22s22p63s23p63d5

Thus the peculiar crystalline structure and the electronic configuration of iron makes it naturally attractive to metals. Thus they are termed ferromagnetic metals. Though they do not contain a single crystalline structure, even then they exhibit different types of allotropic forms. The different allotropic forms of irons are termed alpha, beta and gamma iron. 

(Image Will be Updated Soon)

Properties of Fe

Mostly in hemoglobin and myoglobin, an adult human body contains about 4 grams (0.005% body weight) of iron. The functioning of the vertebrate metabolism, oxygen transport by blood, and oxygen storage in muscles need these two basic proteins for their vital functioning. The human body needs a minimum iron diet in order to maintain the necessary level of human iron metabolism. Iron also acts as an important metal for the active site of many important redox enzymes that are dealing with cellular respiration and oxidation and reduction in both animals and plants.

The most common oxidation states of iron chemically as iron II and iron lll. It shares many of the common properties of other transition metals that are present in group 8 such as ruthenium and osmium. There is a white range of oxidation states in which the iron for mother compounds starts from - 2 to +7. Iron also forms many coordinate compounds some of them are kerosene ferrioxalate and Prussian blue which have vital roles in industrial medical and research applications.

Physical Properties of Iron

Physical Properties

Values of Properties


Luxurious metallic with greyish tinge

The atomic mass of Fe

55.845 (2)

Atomic number








Electronic configuration


Electrons per shell




Melting point

1811 K ​(1538 °C, ​2800 °F)

Boiling Point

3134 K ​(2862 °C, ​5182 °F)


7.874 g/cm3

Density when liquid

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)

Atomic Properties of Iron 

Atomic Properties

Values of Properties

Oxidation state

−4, −2, −1, 0, +1,\[\left [2\right]\] +2, +3, +4, +5,\[\left [3\right]\] +6, +7\[\left [4\right]\]


1.83 on Pauling scale

Ionization energy

1st: 762.5 kJ/mol

2nd: 1561.9 kJ/mol

3rd: 2957 kJ/mol

Atomic radius 

Empirical: 126 pm

Covalent Radius

Low spin: 132±3 pm

High spin: 152±6 pm

Van der Waal radius

194 pm

Spectral line

(Image Will be Updated Soon)

Chemical Properties of Iron

Chemical Properties

Values of Properties

Natural occurrence


Crystal structure

Body centred cubic (bcc) a = 286.65 pm

(Image Will be Updated Soon)  

Face centred cubic (fcc) between 1185 and 1667 K, a = 364.380 pm (Image Will be Updated Soon )

Speed of sound in a thin rod

5120 m/s (electrolytic)

Thermal expansion

11.8 µm/(m⋅K) (at 25 °C)

Thermal conductivity

80.4 W/(m⋅K)

Electrical resistance

96.1 nΩ⋅m (at 20 °C)


1043 K

Magnetic ordering


Young’s module

211 GPa

Shear modulus

82 GPa

Bulk Module

170 Gpa

Poisson ratio


Mohs hardness


Vickers hardness

608 MPa

Brinell hardness

200-1180 MPa

CAS number


Uses of Iron in Daily life

Iron is one of the most essential metals that is found in the earth crust both in the inner and the other layer. Metallic iron has a wide usage both in pure form as well as in alloys for various tools, arms and ammunition and equipment. It has a large application both in its elemental as well as oxide forms. Some of those applications of iron in daily life are listed below:- 

  1. In the Body: It is an important element that contributes to the elements of physiology. It forms an important part of haemoglobin in the red blood cell contained by the body. It is also present in plants and animals in the form of enzymes. The iron that is present in the haemoglobin forms an important element in transporting the oxygen from the lungs to different tissues. 

  2. Iron Supplements: If there is a deficiency of iron in the body then the body suffers from the insufficient oxygen level known as hypochromic anaemia. Ferrous fumarate, ferrous gluconate, ferrous sulfate, etc are used for the iron supplementation. For older people, it is given in the liquid form and for adults, it is given in the form of tablets or capsules. 

  3. In Kitchen and Cookware: Cast iron is the main component of cooking equipment and kitchen wares. Cast iron is specially used for making stones that can be heated with coal or wood. Mini frying pans are also developed from cast iron. Stainless steels are used to make spoons, forks and plates. The frame of the stove is also developed from stainless steel to give it strength and an attractive bright appearance.

  4. Home and Construction Materials: It is widely used in many parts of the world for the construction of homes and for other purposes. Building construction relies mostly on iron rods. It forms the main infrastructure for the pillars, rooftops for buildings and homes.

  5. Plumbing: For transportation of water into different places with pipes are used and these pipes are mainly made up of iron for lifelong stability e off supply without any chance of breakage.

  6. Automobile: Meaning the parts of automobiles are made up of iron except a few where Aluminium is used to give lightweight to the body. The main framework and a few of the other parts of automobiles such as pistons, wheel bearings and wires are made up of iron.

  7. In Agriculture: Iron is a micronutrient and thus it plays a very vital role in the physiology of the plants. Iron deficiency may cause various diseases in plants. Hence iron is used in agriculture to promote the proper growth of plants. Thus the organic ion that is formed by the soil is taken up by the plants for their growth.

FAQs on Fe (Iron)

1. Name the fruit that is high in iron content?

Ans. The fruit that is high in Iron content is Prune juice, olives and mulberries.

2. How does iron help the immune system?

Ans. The body of all animals and humans absorb the heme iron that in turn carries the oxygen from the lungs to different parts of the body and cells that are also part of the immune system. It is also present in the form of enzymes that channelize the immune system as well.