Formula CdI2 Density 5.64 g/cm³ | Molar mass 366.22 g/mol | |
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Appearance white to pale yellow crystals | ||
Cadmium iodide
Cadmium iodide, CdI2, is a chemical compound of cadmium and iodine. It is notable for its crystal structure, which is typical for compounds of the form MX2 with strong polarization effects.
Contents
- Cadmium iodide
- Uses
- Preparation
- Crystal structure
- Iodides
- Chlorides and bromides
- Hydroxides of M2
- Chalcogenides of M4
- Others
- References
Uses
Cadmium iodide is used in lithography, photography, electroplating and the manufacturing of phosphors.
Preparation
Cadmium iodide is prepared by the addition of cadmium metal, or its oxide, hydroxide or carbonate to hydroiodic acid.
Also, the compound can be made by heating cadmium with iodine.
Crystal structure
In cadmium iodide the iodide anions form a hexagonal close packed arrangement while the cadmium cations fill all of the octahedral sites in alternate layers. The resultant structure consists of a layered lattice. This same basic structure is found in many other salts and minerals. Cadmium iodide is mostly ionically bonded but with partial covalent character.
Cadmium iodide's Crystal structure is the prototype on which the crystal structures many other compounds can be considered to be based. Compounds with any of the following characteristics tend to adopt the CdI2 structure:
Iodides
MgI2, TiI2, VI2, MnI2, FeI2, CoI2, CaI2, PdI2, PbI2.
Chlorides and bromides
TiCl2, VCl2;
MgBr2, TiBr2, VBr2, MnBr2, FeBr2, CoBr2.
Hydroxides of M2+
Mg(OH)2, Ni(OH)2, Ca(OH)2.
Chalcogenides of M4+
TiS2, ZrS2, SnS2, α-TaS2, PtS2;
TiSe2, ZrSe2, SnSe2, PtSe2;
SiTe2, TiTe2, CoTe2, NiTe2, PdTe2, PtTe2.
Others
AgF2, W2C.
