Copper(II) chloride, also known as cupric chloride, is an ionic compound of copper and chlorine with the formula CuCl2. It is a brown solid when anhydrous, but turns a brilliant turquoise color when hydrated.
Copper(II) chloride is a brown powder that turns red when molten. Its melting point is 498 °C. In air, it absorbs water to form the dihydrate, which is a neutral tetracoordinate complex. The material normally exists as a brilliant turquoise powder, but thin, transparent, fragile crystals may be grown. In the presense of excess chloride ions, it will form a greener colored acidic copper(II) chloride, in which the water ligands are substituted for chloride ions. Tetrachlorocupric acid is formed.
Copper(II) chloride can oxidize and dissolve aluminium, owing to the formation of the tetrachlorocuprate ion. Besides this, it is a moderate oxidizer and will also dissolve other reactive metals such as zinc and magnesium. It is also useful in organic synthesis because it can chlorinate the alpha position of carbonyls. In the presence of oxygen, it can also oxidize phenols.
Copper chloride can be purchased from chemical suppliers. ScienceCompany sells 100 g of copper(II) chloride dihydrate at 11.95$.
Copper(II) chloride can be produced by adding copper metal to a mixture of hydrochloric acid and hydrogen peroxide. Copper is resistant to attack by pure hydrochloric acid and other non-oxidizing acids, so an oxidizer must be added to promote dissolution (in this case, hydrogen peroxide).
- Make the trichlorocuprate ion
- Make blue fire
Copper(II) chloride is toxic and corrosive, so protection should be worn when handling the compound.
Copper(II) chloride should be stored in closed containers, to keep it dry. The anhydrous form should be kept in sealed containers.
Copper(II) chloride must be reduced with another metal, such as iron to form iron(II) chloride that is less toxic, before being disposed of.