Applications
Diiodomethane is used to determine the density of minerals and other solid samples due to its high density. It is used as an optical contact liquid to determine the refractive index of certain gemstones. In simmons-smith reaction, it acts as a reagent to generate methylene (carbine) free radical. It reacts with olefins to prepare cyclopropanes with high stereo specificity.

Solubility
Miscible with alcohol and ether. Slightly miscible with water.

Notes
Light sensitive. Keep container tightly closed in a dry and well-ventilated place. Incompatible with alkali metal salts, strong oxidizing agents, strong bases, metals, lithium, potassium, sodium, sodium oxides and alloys.