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Iron II Oxide Formula

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  • Last Updated : 13 Sep, 2022
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Iron (II) Oxide is an inorganic compound that has one iron atom and one oxygen atom. Iron is a group 8 element of the periodic table. It is a metal that belongs to the first transition series and is one of the most prevalent elements found on Earth. The atomic number of iron is 26 and is expressed by the symbol Fe. Oxygen is a group of 16 elements of the periodic table and is the third-most abundant element on Earth. The atomic number of oxygen is 8 and is expressed by the symbol O. It is a highly reactive non-metal and a member of the chalcogen group on the periodic table.

Iron (II) Oxide Formula

Iron (II) Oxide belongs to a family of related non-stoichiometric compounds and is made up of iron and oxygen elements. There are various types of iron oxide, and iron II oxide is one of them. Iron (II) oxide is an ionic compound that is also known as ferrous oxide or iron monoxide. FeO is the chemical or molecular formula of Iron (II) Oxide, i.e., it consists of one iron atom and one oxygen atom. Around 9% of the Earth’s crust is made up of iron (II) oxide. Iron (II) oxide occurs as a black crystalline solid, that is widely used to make pigments and dyes used for pottery glazes. A light blue/green crystal is formed when iron II oxide comes in contact with water. Iron II oxide easily oxidizes due to air. It dissolves in acids but is not soluble in water and alkali. It quickly absorbs carbon dioxide and forms iron(II) carbonate (FeCO3) which also happens to be a strong base.

Structure of Iron (II) Oxide

Iron Oxide structure

Iron Oxide structure

Iron (II) oxide is present in a mineral called Wustite that has an octahedral crystal lattice, like that of rock salt. Iron (II) oxide has a cubic, rock salt structure, with iron atoms being octahedrally coordinated by oxygen atoms and oxygen atoms being octahedrally coordinated by iron atoms.

Preparation of Iron (II) Oxide

Iron (II) Oxide occurs naturally as a result of the incomplete oxidation of the metal.

2Fe + O2 → 2FeO

It is synthetically prepared by the thermal decomposition of iron (II) oxalate, which creates iron (II) oxide, carbon dioxide, and carbon monoxide. This procedure has to be conducted under an inert atmosphere so that the formation of iron (III) oxide (Fe2O3) can be avoided.

FeC2O4 → FeO + CO2 + CO

Properties of Iron (II) Oxide

Chemical formula  FeO
Molar Mass   71.844 g/mol
Density   5.745 g/cm3
Appearance 

Solid at room temperature

(Black crystals)

Solubility

Insoluble in water and alkali.

Soluble in Acids

Boiling point   3,414 °C
Melting point   1,377 °C
Magnetic Susceptibility +7200·10−6 cm3/mol
Refractive Index 2.23

Chemical Properties of Iron (II) Oxide

  • Below 575 °C, FeO is thermodynamically unstable and tends to be disproportionate to metals and Fe3O4.

4FeO → Fe + Fe3O4

  • It easily gets oxidized if exposed to air and produces iron(III) oxide.

4FeO + O2 → 2Fe2O3

  • Iron II Oxide (FeO) dissolves in sulphuric acid (H2SO4) and forms Iron (III) sulfate or ferric sulfate.

2FeO + 4H2SO4 → Fe2(SO4)3 +4H2O + SO2

  • Iron II Oxide (FeO) dissolves in nitric acid (HNO3) and forms Ferric nitrate or Iron (III) nitrate.

3FeO + 10HNO3 → 5H2O + NO + 3Fe(NO3)3

  • Iron II Oxide (FeO) reacts with hydrogen chloride (HCl) and produces Iron(II) chloride and water.

FeO + 2HCl → FeCl2 + H2O

  • Iron II Oxide (FeO) reacts with silver nitrate(AgNO3) and produces Silver oxide and Ferrous Nitrate.

2AgNO3 + FeO → Ag2O + Fe(NO3)2

Uses of Iron II Oxide

  • Iron (II) oxide is used as a pigment, and dyes are used for pottery glazes. 
  • It has FDA approval for usage in cosmetics and is used in some tattoo inks. 
  • It is used as a raw material to produce the steel that is used to construct buildings and manufacture cars. 
  • In its green crystallized form, it is a component of the heat-absorbing glass that is used in automobiles and buildings.
  • It is used as a catalyst in industrial operations.
  • It can also be used as a phosphate remover in home aquaria.

Hazards

  •  A high level of exposure to iron (II) oxide may cause illness with flu-like symptoms and siderosis. 
  • Inhalation of fumes or dust of iron (II) oxide is hazardous as it may cause throat and nasal irritation.

FAQs on Iron(II) Oxide Formula

Question 1: What is Iron (II) oxide?

Answer: 

Iron (II) Oxide belongs to a family of related non-stoichiometric compounds and is made up of iron and oxygen elements. There are various types of iron oxide, and iron II oxide is one of them. Iron (II) oxide is an ionic compound that is also known as ferrous oxide or iron monoxide. FeO is the chemical or molecular formula of Iron (II) Oxide, i.e., it consists of one iron atom and one oxygen atom.

Question 2: How is Iron (II) oxide prepared?

Answer:

Iron (II) Oxide occurs naturally as a result of the incomplete oxidation of the metal.

2Fe + O2 → 2FeO

It is synthetically prepared by the thermal decomposition of iron (II) oxalate, which creates iron (II) oxide, carbon dioxide, and carbon monoxide. This procedure has to be conducted under an inert atmosphere so that the formation of iron (III) oxide (Fe2O3) can be avoided.

FeC2O4 → FeO + CO2 + CO

Question 3: What happens when water comes in contact with Iron (II) oxide?

Answer:

A light blue/green crystal is formed when iron II oxide comes in contact with water. In this form, it happens to be a component of green heat-absorbing glass that is used in automobiles and buildings. Greenish-colored glass is used for tinting the glasses used in some greenhouses where plants are grown indoors.

Question 4: Is Iron (II) oxide hazardous to health?

Answer:

Yes, iron (II) oxide is hazardous to health. A high level of exposure to iron (II) oxide may cause illness with flu-like symptoms and siderosis. Inhalation of fumes or dust of iron (II) oxide is hazardous as it may cause throat and nasal irritation.

Question 5: Write any four uses of Iron (II) oxide.

Answer:

  1. Iron (II) oxide is used as a pigment, and dyes are used for pottery glazes. 
  2. It has FDA approval for usage in cosmetics and is used in some tattoo inks. 
  3. It is used as a raw material to produce the steel that is used to construct buildings and manufacture cars. 
  4. In its green crystallized form, it is a component of the heat-absorbing glass that is used in automobiles and buildings.

Question 6: Calculate the Molecular weight of Iron (II) oxide.

Answer:

Iron (II) Oxide is an inorganic compound that has one iron atom and one oxygen atom. 

The atomic weight of each Iron atom = 55.845 g/mol

The atomic weight of each oxygen atom = 15.999 g/mol

So, the molar mass of FeO = 1 × 55.845 + 1 × 15.999

= 71.844 g/mol

Hence, the molar mass of Iron (II) Oxide is 71.844 g/mol.

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