Silver iodide is an inorganic compound which is highly photosensitive (reacts when exposed to light). It is also called silver (I) iodide or iodargyrite. Formula and structure: The chemical formula of silver iodide is AgI and its molar mass is 234.77 g/mol. It is an inorganic compound composed of the silver metal (Ag) and the iodine atom (I), attached through a polar covalent bond having a strong ionic character.