What is the chemical formula of iron(Ill) sulfide? Chemistry Ionic Bonds Writing Ionic Formulas 1 Answer anor277 Jan 28, 2016 #Fe_2S_3#; i.e. an analogue of ferric oxide, #Fe_2O_3#. Explanation: See this site. Sulfur typically has a #-2# oxidation state (it is a Group VI atom, and its redox chemistry follows that of oxygen). And #Fe^(3+)#, ferric ion, has a #+3# oxidation state. We cross multiply and get the given formula. Answer link Related questions How do you write ionic formulas for binary compounds? What is the ionic formula for calcium chloride? What is the ionic formula for calcium oxide? What is the ionic formula for lithium oxide? How do you write the formula for ionic compounds? How do I write #Sn(NO_3)_2# in Ionic formula? What is the empirical formula for an ionic compound? What is the molecular formula for chorate? Question #7086b Why are polyatomic ions covalent? See all questions in Writing Ionic Formulas Impact of this question 3893 views around the world You can reuse this answer Creative Commons License