Copper(II) chloride  Copper(II) chloride is the chemical
compound with the formula CuCl2. This a yellow-brown solid which
slowly absorbs moisture to form a blue-green dihydrate.
Anhydrous CuCl2 adopts a distorted cadmium iodide structure.
Most copper(II) compounds exhibit distortions from idealized
octahedral geometry due to the Jahn-Teller effect, which in this
case describes the localisation of one d-electron into a
molecular orbital that is strongly antibonding with respect to a
pair of ligands. In CuCl2(H2O)2 the copper can be described as a
highly distorted octahedral complex, the Cu(II) center being
surrounded by two water ligands and four chloride ligands, which
bridge asymmetrically to other Cu centers.   Copper(II) chloride
dissociates in aqueous solution to give the blue color of
[Cu(H2O)6]2+ and yellow or red color of the halide complexes of
the formula [CuCl2+x]x-. Concentrated solutions of CuCl2 appear
green because of the combination of these various chromophores.
The color of the dilute solut