Flexi Says: A binary ionic compound is a compound composed of a monatomic metal cation and a monatomic nonmetal anion. Eg: KF (potassium fluoride)
A ternary ionic compound is an ionic compound composed of three or more elements. In a typical ternary ionic compound, there is still one type of cation and one type of anion involved. The cation, the anion, or both, is a polyatomic ion. Eg: Fe(OH)3 (iron(III) hydroxide)
