Promethium(III) iodide

Promethium(III) iodide is an inorganic compound, with the chemical formula of PmI3. It is a red radioactive solid with a melting point of 695 °C.

Preparation
Promethium(III) iodide is obtained by reacting anhydrous hydrogen iodide and promethium(III) chloride at a high temperature:


 * PmCl3 + 3 HI → PmI3 + 3 HCl

From the reaction of a HI-H2 mixture and promethium oxide (Pm2O3), promethium(III) iodide cannot be produced, and only promethium oxyiodide (PmOI) can be obtained. Promethium oxide reacts with molten aluminum iodide at 500°C to form promethium iodide.