Lewis Structure of iron (III) oxide, Fe2O3, step-by-step

The Lewis Structure of iron (III) oxide, Fe2O3, consists of five ions: Two iron ions with a +3 charge each, and three oxygen ions with a -2 charge each.

Iron III oxide is an ionic compound, because it consists of a metal and non-metal. These types of atoms have a big enough electronegativity difference that electrons are *transferred* from one atom to another, rather than being shared.

To begin, we note that the iron atoms need a charge of +3 … this is evident in the chemical formula (Fe2O3), since the “3” on the O had to have been criss-crossed down from the iron. It is also obvious in the name: The Roman numeral (III) after iron indicates that its charge in this compound is +3.

So we draw two iron atoms with three valence electrons each.

Each oxygen atom brings 6 valence electrons (Oxygen is in Group 16 and is two electrons short of a full octet in its outer shell).

This image shows the transfer of electrons from Iron atoms to Oxygen Atoms, and the complete lewis structure of Iron (III) Oxide, Fe2O3.

One iron atom gives two electrons to an oxygen, but then still has one electron left. So it gives that electron to another oxygen, but that oxygen requires one more as well. So another iron atom must come into play; it gives one electron to complete the second oxygen’s octet and then gives away both of its leftover electron to a third oxygen.

This is an ionic compound, so there is no “hybridization of oxygen in Fe2O3” – it is instead a lattice of alternating positive and negative ions.

This structure likely reminds you of the lewis structure of Calcium Bromide (CaBr2), which was also ionic.

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