The formula for iron(III) nitrate is Fe(NO₃)₃. Here's how to break it down:

* Fe: Represents the iron ion. The Roman numeral "III" indicates that iron has a +3 charge (Fe³⁺).

* NO₃: Represents the nitrate ion, which has a -1 charge (NO₃⁻).

To balance the charges, you need three nitrate ions for every iron(III) ion. This gives you the final formula: Fe(NO₃)₃.