Iron Oxide Formula

Iron Oxide

Iron Oxide Formula- It is a chemical compound. In nature, it occurs as the mineral magnetite. Also, it is one of the three major oxides of iron, the other is iron ii oxide (FeO) that is rare, and the other is iron iii oxide ( \( Fe_{2}O_{3}\) ) that we call hematite. Furthermore, it contains both \( Fe^{2+} \) and \( Fe^{3+} \) ions and is sometimes formulated as \( FeO \cdot Fe_{2}O_{3} \). In laboratories, this iron oxide is encountered as a black powder. Moreover, it shows permanent magnetism and is ferrimagnetic.

Iron oxide Formula and Structure

The chemical formula of iron iii oxide is  \( Fe_{3}O_{4} \). It has a cubic inverse spinel group structure which comprises of a cubic closely filled array of oxide ions where all the \( Fe^{2+} \) ions occupy half of the octahedral places and the \( Fe^{3+} \) are split consistently transversely the leftover octahedral sites and the tetrahedral sites. In addition, the ferrimagnetism of  \( Fe_{3}O_{4} \) ascends due to the electron spins of the \( Fe^{II} \) and \( Fe^{III} \) ions in the octahedral sites.

Occurrence of iron oxide

Ferric oxide occurs in crystals of the cubic system, as loose sand, and in masses. Moreover, it is one of the most important magnetic ores of iron and its common constituents of metamorphic and igneous rocks. It generally occurs in nature as the mineral magnetite. It also occurs as a nano-crystals in magnetotactic bacteria (42-45 nm) and in the beak tissue of homing pigeons.

Preparation of iron oxide

Underneath anaerobic situations, ferrous hydroxide ( \( Fe(OH)_{2} \) ) which is oxidized by the water to form magnetite and molecular hydrogen. Furthermore, the Schikorr reaction describe this process as:

\( 3 Fe(OH)_{2} \rightarrow Fe_{3}O_{4} + H_{2} + 2 H_{2}O \)

However, the well-crystallized magnetite ( \( Fe_{3}O_{4} \) ) is thermodynamically more stable than the ferrous hydroxide ( \( Fe(OH)_{2} \) ).

Properties of iron oxide

Ferric oxide is ferromagnetic with a Curie temperature of 858 K. In addition, there is a phase transition at 120K that we call Verwey transition. In this, there is a discontinuity in the structure, magnetic properties, and conductivity. Besides, this effect has been extensively investigated and whilst various explanations have been proposed. But it does not appear to be fully understood. It is a conductor of electricity that conducts significantly higher (X \( 10^{6}\) ) than \( Fe_{2}O_{3} \). And we can describe it as an electronic exchange between the  \( Fe^{II} \) and \( Fe^{III} \) centers.

Uses of iron oxide

We use it as a black pigment that we call as C.I pigment Black 11 or Mars black. We use it as a catalyst in the Haber process and in the water-gas shift reaction. Furthermore, its latter uses are as an HTS (high temperature shift catalyst) of iron oxide that we can stabilize by chromium oxide. Moreover, at the reactor start-up the iron-chrome catalyst is reduced to generate \( Fe_{3}O_{4} \) from \( \alpha- Fe_{2}O_{3} \)  and \(Cr_{2}O_{3}\) to \(CrO_{3} \).

We use Nanoparticles of ferric oxide as a contrast agent in MRI scanning. In addition, the ferumoxytol that we also know by the names Rienzo and Feraheme is an intravenous \( Fe_{3}O_{4} \) preparation for treatment of anemia resulting from chronic kidney disease.

Solved example for you

Question: Mention a reaction of magnetite?

Solution: We use the reduction of magnetite ore by CO in a blast furnace to produce iron as part of the steel production process:

\( Fe_{3} O_{4} + 4 CO \rightarrow 3 Fe + 4 CO_{2} \)