Copper chloride is the chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 CuCl₂. This is a light brown solid, which slowly absorbs moisture to form a blue-green dihydrate

Water of crystallization

In crystallography, water of crystallization or water of hydration or crystallization water is water that occurs in crystals. Water of crystallization is necessary for the maintenance of crystalline properties, but capable of being removed by sufficient heat...

. The copper(II) chlorides are some of the most common copper(II) compounds, after copper sulfate.
Anhydrous CuCl₂ adopts a distorted cadmium iodide

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.-Uses:...

 structure. In this motif, the copper centers are octahedral

Octahedral molecular geometry

In chemistry, octahedral molecular geometry describes the shape of compounds where in six atoms or groups of atoms or ligands are symmetrically arranged around a central atom, defining the vertices of an octahedron...

. Most copper(II) compounds exhibit distortions from idealized octahedral geometry due to the Jahn-Teller effect

Jahn-Teller effect

The Jahn–Teller effect, sometimes also known as Jahn–Teller distortion, or the Jahn–Teller theorem, describes the geometrical distortion of non-linear molecules under certain situations. This electronic effect is named after Hermann Arthur Jahn and Edward Teller, who proved, using group theory,...

, which in this case describes the localization of one d-electron into a molecular orbital

Molecular orbital

In chemistry, a molecular orbital is a mathematical function describing the wave-like behavior of an electron in a molecule. This function can be used to calculate chemical and physical properties such as the probability of finding an electron in any specific region. The term "orbital" was first...

 that is strongly antibonding with respect to a pair of chloride ligands.