Cerium(III) iodide (CeI<sub>3</sub>) is the compound formed by cerium(III) cations and iodide anions.
Cerium metal reacts with iodine when heated to form cerium(III) iodide:
It is also formed when cerium reacts with mercury(II) iodide at high temperatures:
Cerium(III) iodide adopts the plutonium(III) bromide crystal structure. It contains 8-coordinate bicapped trigonal prismatic Ce<sup>3+</sup> ions.
Cerium(III) iodide is used as a pharmaceutical intermediate and as a starting material for organocerium compounds.