Terbium(III) iodide

Terbium(III) iodide (TbI3) is an inorganic chemical compound.

Preparation
Terbium(III) iodide can be produced by reacting terbium and iodine.


 * 2 Tb + 3 I2 -> 2 TbI3

Terbium iodide hydrate can be crystallized from solution by reacting hydriodic acid with terbium, terbium(III) oxide, terbium hydroxide or terbium carbonate:


 * 2 Tb + 6 HI → 2 TbI3 + 3 H2↑
 * Tb2O3 + 6 HI → 2 TbI3 + 3 H2O
 * 2 Tb(OH)3 + 6 HI → 2 TbI3 + 3 H2O
 * Tb2(CO3)3 + 6 HI → 2 TbI3 + 3 H2O + 3 CO2

An alternative method is reacting terbium and mercury(II) iodide at 500 °C.

Structure
Terbium(III) iodide adopts the bismuth(III) iodide (BiI3) crystal structure type, with octahedral coordination of each Tb3+ ion by 6 iodide ions.