Diiodomethane is a colorless liquid; however, it decomposes upon exposure to light liberating iodine, which colours samples brownish.
D 1895 (OTTO) Diiodomethane, 98% Cas 75-11-6 - used in the determination of the density of mineral and other solid samples. D 1895 (OTTO) Diiodomethane, 98% Cas 75-11-6 - used as an optical contact liquid, in conjunction with the gemmological refractometer, for determining the refractive index of certain gemstones.