Difference Between Fe2O3 and Fe3O4

Fe2O3 vs Fe3O4

The difference between Fe2O3 and Fe3O4 can be discussed in terms of their chemical as well as physical properties and usage. Both of these minerals are naturally occurring iron oxides. But, most of their properties and usages are different to each other. The natural form of Fe2O3 is called hematite, and that of Fe3O4 is called magnetite. They both are colorful oxides with different colours, which are used as pigments and possess ferromagnetic properties.

What is Fe2O3?

The mineral form of Fe2O3 is called hematite or haematite. The IUPAC name of this compound is iron (III) oxide, also known as ferric oxide. It is an inorganic compound that has several phases of crystal structures. It is dark red in color.

Fe2O3 is the main source of iron in steel and iron industry, and it is used to produce some alloys. The fine powder of Fe2O3 is a polishing agent for metallic jewelry and lenses. Fe2O3, when used as a pigment, has different names. Those names are “Pigment Brown 6,” “Pigment Brown 7,” and “Pigment Red 101.” They are used in medical activities and in paint industry. For example, “Pigment Brown 6″ and “Pigment Red 101″ are FDA (Food and Drug Administration) approved colours and used to make cosmetics. A combination of iron oxides and titanium oxide is used as a pigment in dental composite.

Difference Between Fe2O3 and Fe3O4

What is Fe3O4?

Fe3O4 contains both Fe2+ and Fe3+ ions. Therefore, it is called Iron (II) (III) oxide. The IUPAC name of Fe3O4 is iron (II) iron (III) oxide. It is also known as ferrous-ferric oxide. It can be formed by FeO and Fe2O3, The natural form of this mineral is magnetite. It possesses magnetic properties and it is the most magnetic mineral found on the earth. It naturally occurs in almost all igneous and metamorphic rocks as small grains. It is black or brownish-black in colour with a metallic luster.

There are several commercial usages of Fe3O4. It is a catalyst in industrial synthesis of ammonia using “Haber process.” It is also used to make black pigment called C.I pigment black 11 (C.I. No.77499). Nano-particles of Fe3O4 are used in MRI scanning process as a contrasting agent. The powdered form of Fe3O4 is a good sorbent; it removes arsenic (III) and arsenic (V) from water.

 Fe2O3 vs Fe3O4

What is the difference between Fe2O3 and Fe3O4?

• Structure:

• The Fe2O3 has several crystal forms as alpha phase, gamma phase, and other phases. Alpha-Fe2O3 has the rhombohedral structure, gamma- Fe2O3 has the cubic structure, and beta phase has cubic body-centered structure.

• The crystal structure of Fe3O4 is “cubic inverse spinel structure.”

Oxidation state of iron (Fe):

• In Fe2O3 , the oxidation state of iron is (+III).

• Fe3O4 contains both (+II) and (+III) oxidation states.

• Colour:

• Fe2O3 is dark red in colour. It appears as a red-brown solid.

• Fe3O4 has a brownish-black colour with a metallic luster.

Electrical Conductivity:

• The electrical conductivity of Fe3O4 is significantly higher (* 106) than Fe2O3. The reason for this property is due to the ability to exchange electrons between Fe2+ and Fe3+ centers in Fe3O4.

• As a Pigment:

• Fe2O3 produces several colours as a pigment; “Pigment Brown 6,” “Pigment Brown 7,” and “Pigment Red 101.”

• Fe3Ois used to make black color pigment called C.I pigment black 11.


Images Courtesy:

  1. Sample of iron(III) oxide via Wikicommons (Public Domain)
  2. Fe3O4 by Leiem (CC BY-SA 4.0)
  • Kevin Rhoades

    Will the black powder work with thermite too?