Cerium diiodide is an iodide of cerium, with the chemical formula of CeI<sub>2</sub>.
Cerium diiodide can be obtained from the reduction of cerium(III) iodide with metallic cerium under vacuum at 800 ðC to 900 ðC.
It can also be formed from the reaction of cerium and ammonium iodide in liquid ammonia at âÂÂ78 ðC. The reaction forms an ammonia complex of cerium diiodide, which decomposes to cerium diiodide under vacuum at 200 ðC.
It was first created by John D. Corbett in 1961.
Cerium diiodide is an opaque dark solid with a metal-like appearance and properties. There is no cerium(II) in cerium diiodide, and its real structure is Ce<sup>3+</sup>(I<sup>âÂÂ</sup>)<sub>2</sub>e<sup>âÂÂ</sup>. It is easily hydrolyzed to form the corresponding oxyiodide. Like lanthanum diiodide and praseodymium diiodide, the cerium diiodide forms in the MoSi<sub>2</sub>-type structure, with space group I4/mmm (No. 139).