Cadmium iodide is an important inorganic solid for fundamental scientific research. The structure is a simple I-Cd-I layered structure with [CdI6]4- octahedron being the basic building block. There are many ways of stacking the layers which result in many polytypes. Till now several hundreds of polytypes have been reported. Taking into account some known structures of CdI2 worked out earlier and work done on the purification of material it is noted that the presence of impurities in the starting material distorts the [CdI6]4- octahedron, which in turn give rise to formation of polytypes
