Iridium(II) chloride

Iridium(II) chloride is an inorganic chemical compound of iridium metal and chlorine with the chemical formula IrCl2. This is a metal salt of iridium and hydrochloric acid.

Synthesis

 * The substance is obtained by the interaction of powdered metallic iridium with chlorine gas when heated:


 * Ir + Cl2 -> IrCl2


 * Iridium(II) chloride can also be made in a reaction between iridium(III) chloride and metallic iridium:


 * 2IrCl3 + Ir -> 3IrCl2

Physical properties
Iridium dichloride forms shiny dark-green crystals that are practically insoluble in water. Poorly soluble in acids and alkali. When heated to 773 °C, IrCl2 decomposes without melting.

The standard Gibbs energy of the formation of ΔG (298 K, kJ/mol) is -139.7.

Chemical properties
When heated to 773 °C decomposes according to the equation:


 * 2IrCl2 -> 2IrCl + Cl2

At temperatures above 798 °C, complete decomposition of the substance occurs:


 * IrCl2 -> Ir + Cl2