It is bright yellow but upon time and exposure to light it turns red due to the presence of elemental iodine.

In the solid state is present as a planar dimer I2Cl6, with two bridging Cl atoms.

[1] It can be prepared by reacting iodine with an excess of liquid chlorine at −70 °C,[2] or heating a mixture of liquid iodine and chlorine gas to 105 °C.

[citation needed] In the molten state it is conductive, which may indicate dissociation:[2] It is an oxidizing agent, capable of causing fire on contact with organic materials.

[citation needed] That oxidizing power also makes it a useful catalyst for organic chlorination reactions.