What is the formula for sodium peroxide? Chemistry Ionic Bonds Writing Ionic Formulas 1 Answer anor277 Jul 15, 2016 #Na_2O_2# Explanation: Oxygen in peroxide dianion has a formal #-I# oxidation state. Is this consistent with the given charge of the ion? 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 3974 views around the world You can reuse this answer Creative Commons License