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Diiodomethane

Diiodomethane
Stereo, skeletal formula of diiodomethane with all explicit hydrogens added
Ball and stick model of diiodomethane
Spacefill model of diiodomethane
Names
IUPAC name
Diiodomethane
Identifiers
3D model (Jmol)
1696892
ChemSpider
ECHA InfoCard 100.000.765
EC Number 200-841-5
MeSH methylene+iodide
PubChem CID
RTECS number PA8575000
Properties
CH2I2
Molar mass 267.84 g·mol−1
Appearance Colorless liquid
Density 3.325 g mL−1
Melting point 5.4 to 6.2 °C; 41.6 to 43.1 °F; 278.5 to 279.3 K
Boiling point 182.1 °C; 359.7 °F; 455.2 K
1.24 g L−1 (at 20 °C)
23 μmol Pa−1 kg−1
-93.10·10−6 cm3/mol
Structure
Tetragonal
Tetrahedron
Thermochemistry
133.81 J K−1 mol−1
67.7–69.3 kJ mol−1
−748.4–−747.2 kJ mol−1
Hazards
Safety data sheet hazard.com
GHS pictograms The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
H302, H315, H318, H335
P261, P280, P305+351+338
Harmful Xn
R-phrases R22, R36/37/38
S-phrases S26
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 110 °C (230 °F; 383 K)
Related compounds
Related alkanes
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

Diiodomethane or methylene iodide, commonly abbreviated "MI", is an organoiodine compound. Diiodomethane is a colorless liquid; however, it decomposes upon exposure to light liberating iodine, which colours samples brownish. It is slightly soluble in water, but soluble in organic solvents. It has a relatively high refractive index of 1.741, and a surface tension of 0.0508 N·m−1.

Because of its high density, diiodomethane is used in the determination of the density of mineral and other solid samples. It can also be used as an optical contact liquid, in conjunction with the gemmological refractometer, for determining the refractive index of certain gemstones. Diiodomethane is a reagent in the Simmons–Smith reaction, serving as a source of the free radical methylene (carbene), :CH
2.

Although commercially available, it can be prepared by reducing iodoform with elemental phosphorus or sodium arsenite:

Diiodomethane can also be prepared from dichloromethane by the action of sodium iodide in acetone in the Finkelstein reaction:

Alkyl iodides are alkylating agents and contact should be avoided.


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