Cerium diiodide
Chemical compound
From Wikipedia, the free encyclopedia
Cerium diiodide is an iodide of cerium, with the chemical formula of CeI2.
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| Identifiers | |
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3D model (JSmol) |
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| Properties | |
| CeI2 | |
| Molar mass | 393.925 g·mol−1 |
| Appearance | bronze solid[1] |
| Melting point | 808 °C[1] |
| Structure | |
| I4/mmm (No. 139) | |
| Related compounds | |
Other cations |
lanthanum diiodide praseodymium diiodide neodymium(II) iodide |
Related compounds |
cerium(III) iodide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation
Cerium diiodide can be obtained from the reduction of cerium(III) iodide with metallic cerium under vacuum at 800 °C to 900 °C.[2]
- Ce + 2 CeI3 → CeI2
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]
- Ce + 2 NH4I → CeI2 + 2 NH3 + H2
It was first created by John D. Corbett in 1961.[3]
Properties
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 Ce3+(I−)2e−. It is easily hydrolyzed to form the corresponding oxyiodide.[2] Like lanthanum diiodide and praseodymium diiodide, the cerium diiodide forms in the MoSi2-type structure,[4] with space group I4/mmm (No. 139).[5]