Promethium(III) iodide is an inorganic compound, with the chemical formula of PmI<sub>3</sub>. It is a red radioactive solid with a melting point of 695 ðC.
Promethium(III) iodide is obtained by reacting anhydrous hydrogen iodide and promethium(III) chloride at a high temperature:
From the reaction of a HI-H<sub>2</sub> mixture and promethium oxide (Pm<sub>2</sub>O<sub>3</sub>), promethium(III) iodide cannot be produced, and only promethium oxyiodide (PmOI) can be obtained. Promethium oxide reacts with molten aluminum iodide at 500 ðC to form promethium iodide.