Diiodomethane

Diiodomethane or methylene iodide is liquid halomethane insoluble in water, soluble in ether and alcohol. It has high refractive index of 1.741. Fresh diiodomethane is a colorless liquid. However, its exposition to light causes it to slowly decompose and deliberate iodine, which colours it brownish.

With its high specific gravity, it is used for the separation of minerals or for determination of specific gravity of mineral particles. Due its uncertain toxicity, it should be replaced with safer heavy liquids. It is also used as a solvent and a chemical intermediate.