Chemistry: A Molecular Approach (3rd Edition)

The charge on Fe must be 3+ for the compound to be charge-neutral with three $O^{2-}$ anions. The name for $Fe_{2}O_{3}$ is the name of the cation, iron, followed by the charge of the cation in parentheses (III) and the base name of the anion, ox, with the ending - ide. The full name is iron(III) oxide.