An iodide ion's an iodine atom with a −1 charge. Compounds with iodine in formal oxidation state −1 are called iodides. This can include ionic compounds such as caesium iodide or covalent compounds such as phosphorus triiodide. This's the same naming scheme as's seen with chlorides and bromides. The chemical test for an iodide compound's to acidify the aqueous compound by adding some drops of acid, to dispel any carbonate ions present, then adding lead(II) nitrate, yielding a bright… (More on Iodide)