Name ionic compounds containing polyatomic ions the same way as other ionic compounds, but use the polyatomic ion name whenever it occurs. (See Related eHows, "How to Name Ionic Compounds" and "How to Name Binary Ionic Compounds."
Pull up a table of common polyatomic ion names from a website when naming ionic compounds (See Resources). Name NaNO2 like this: Na+ is sodium, a cation, NO2- is the polyatomic ion nitrite; sodium nitrite is the name of the ionic compound with a polyatomic ion.
Know that some metals form more than one kind of cation. For instance, chromium, iron and cobalt all have a 2+ cation and a 3+ cation. Tin and lead both have a 2+ cation and a 4+ cation. Note this in the name of the ion by Roman numerals. For instance, write iron(II) or iron(III), tin(II) or tin(IV) according to the charge.
Understand that the overall charge on an ionic compound is always neutral. Use the name of the polyatomic ion in the compound with the name of the metal with the Roman numeral charge noted. For example, the name for FeSO4 is iron(II) sulfate. Because SO4 is the sulfate polyatomic ion, and it has a charge of 2-, the overall charge of the ionic compound iron(II) sulfate is a neutral charge.
Recognize when an ionic compound contains two polyatomic ions and use both names for the name of the compound. For example, NH4 is ammonium, NO3 is nitrate. Both of these are polyatomic ions. Together the name for this ionic compound containing polyatomic ions is ammonium nitrate.