Question

What is the formula unit for a compound made from Fe3+ and oxygen?

FeO3
O3Fe
Fe2O3
O3Fe2

Answers

GPT-4o mini
The correct formula unit for a compound made from Fe³⁺ (iron in the +3 oxidation state) and oxygen is **Fe₂O₃**.

In this compound, two iron ions (Fe³⁺) combine with three oxide ions (O²⁻) to achieve electrical neutrality. Therefore, the correct choice is **Fe₂O₃**.