Dysprosium(II) iodide

Dysprosium(II) iodide is an iodide of dysprosium with the chemical formula DyI2.

Preparation
Dysprosium(II) iodide can be produced by reducing dysprosium(III) iodide with metallic dysprosium under a vacuum at 800 to 900 °C:


 * Dy + 2 DyI3 -> 3 DyI2

It can also be formed by the reaction of dysprosium and mercury(II) iodide:


 * Dy + HgI2 -> DyI2 + Hg

It can also be formed by the direct reaction of dysprosium and iodine.


 * Dy + I2 -> DyI2

Properties
Dysprosium(II) iodide is a dark purple-black solid that is easily deliquescent and can only be stored in a dry inert gas or a vacuum. In the air, it will absorb moisture and become a hydrate, but they are unstable and will quickly convert into iodide oxides and release hydrogen gas. This process occurs faster in the presence of water. This compound has the same crystal structure as cadmium chloride. It can form complexes with tetrahydrofuran, butanol and phenol.

Uses
The reaction between dysprosium(II) iodide and silicon tetrachloride produces trichlorosilyl radicals, which can catalyze the trimerization of alkynes.