[2] It can also be formed from the reaction of cerium and ammonium iodide in liquid ammonia at −78 °C.

The reaction forms an ammonia complex of cerium diiodide, which decomposes to cerium diiodide under vacuum at 200 °C.

[2] It was first created by John D. Corbett in 1961.

[3] Cerium diiodide is an opaque dark solid with a metal-like appearance and properties.

It is easily hydrolyzed to form the corresponding iodide oxide.