What chareristic is most shared by most simple polyomatic ions

Answer;

They are anions.

Explanation; Polyatomic ions are the ions that contain 2 or more different atoms that are covalently bonded to each other. Examples include; Nitrate : NO₃⁻, Sulfate : SO₄²⁻, Hydroxide : OH⁻, and Phosphate : PO₄³⁻, etc. Polyatomic ions are tightly bound group of atoms that has a positive or negative charge and behaves as a unit.