Terbium(III) iodide (TbI<sub>3</sub>) is an inorganic chemical compound.
Terbium(III) iodide can be produced by reacting terbium and iodine.
Terbium iodide hydrate can be crystallized from solution by reacting hydriodic acid with terbium, terbium(III) oxide, terbium hydroxide or terbium carbonate:
An alternative method is reacting terbium and mercury(II) iodide at 500 ðC.
Terbium(III) iodide adopts the bismuth(III) iodide (BiI<sub>3</sub>) crystal structure type, with octahedral coordination of each Tb<sup>3+</sup> ion by 6 iodide ions.