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Chromium(II) iodide

Chromium(II) iodide is the inorganic compound with the formula CrI<sub>2</sub>. It is a red-brown or black solid. The compound is made by thermal decomposition of chromium(III) iodide. Like many metal diiodides, CrI<sub>2</sub> adopts the "cadmium iodide structure" motif, i.e., it features sheets of octahedral Cr(II) centers interconnected by bridging iodide ligands. Reflecting the effects of its d<sup>4</sup> configuration, chromium's coordination sphere is highly distorted.

Treatment of chromium powder with concentrated hydroiodic acid gives a blue hydrated chromium(II) iodide, which can be converted to related acetonitrile complexes.

Cr + nH<sub>2</sub>O + 2HI → CrI<sub>2</sub>(H<sub>2</sub>O)<sub>n</sub> + H<sub>2</sub>

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