| Boiling Point | 181°C/1013 hPa (decomposition) |
| Melting Point | 6°C |
| Density | 3.3 g/cm³ at 20°C |
| Color | Yellow |
| Formula Weight | 267.84 |
| Physical Form | Liquid |
| Chemical Name or Material | Diiodomethane (stabilized with copper chip) |
| UN Number | 1760 |
| Molecular Weight | 267.84 g/mol |
| SMILES String | ICI |
| Solubility | 0.8 g/L (water) |
| CAS Number | 75-11-6 |
| Storage Temperature | 2–30°C |
| Empirical Formula | CH2I2 |
| NACRES | NA.22 |
| UNSPSC Code | 12352101 |
| MDL Number | MFCD00001079 |
| InChI | 1S/CH2I2/c2-1-3/h1H2 |
| InChI Key | NZZFYRREKKOMAT-UHFFFAOYSA-N |
| Quality Level | 200 |
| Reference Assay | ≥98% (GC) |
| Applications | Heavy liquid for mineral and particle density-gradient separation |
Diiodomethane is a simple halomethane in which two hydrogen atoms of methane are replaced by iodine, giving it one of the highest densities of any common laboratory liquid (approximately 3.3 g/cm³) along with a notably high refractive index. Because the carbon-iodine bonds are relatively weak and light-sensitive, commercial diiodomethane is typically stabilized with a small copper chip to scavenge liberated iodine and slow decomposition.
Its exceptional density makes diiodomethane a go-to heavy liquid for separating minerals or particles by density gradient — materials less dense than the liquid float, denser ones sink. Its high refractive index is separately useful as an optical reference standard and in contact-angle/surface-energy research. In organic synthesis, it also serves as a methylene-transfer reagent in select cyclopropanation-type reactions.
