CAS number 75-11-6 YesY
PubChem 6346
ChemSpider 6106 YesY
EC number 200-841-5
RTECS number PA8575000
Jmol-3D images Image 1
Molecular formula CH2I2
Molar mass 267.84 g/mol
Appearance Colorless liquid with chloroform-like odour
Density 3.325 g/cm3
Melting point

6 °C, 279 K, 43 °F

Boiling point

181 °C (358 °F) (decomp.)

Solubility in water 14 g/l at 20 °C
MSDS MSDS at the University of Oxford, J.T.Baker MSDS
EU classification Harmful (Xn)
R-phrases R20/22
S-phrases S26, S27, S36/37/39
NFPA 704
NFPA 704.svg
Flash point 113 °C
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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

With its high specific gravity, diiodomethane is used in the determination of the density of mineral and other solid samples. It is also used as a contact liquid for refractometers. Diiodomethane is a reagent in the Simmons-Smith reaction, serving as a source of methylene CH2.[2]



Although commercially available, it can be prepared by reducing iodoform with sodium arsenite:[3]

CHI3 + Na3AsO3 + NaOH → CH2I2 + NaI + Na3AsO4

Diiodomethane can also be prepared from dichloromethane by the action of sodium iodide in acetone in the Finkelstein reaction:[3]

CH2Cl2 + 2 NaI → CH2I2 + 2 NaCl


Alkyl iodides are alkylating agents and contact should be avoided.


  1. ^ Website of Krüss (8.10.2009)
  2. ^ Two cyclopropanation reactions: Smith, R. D.; Simmons, H. E., "Norcarane", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv5p0855 ; Coll. Vol. 5: 855 , Ito, Y.; Fujii, S.; Nakatuska, M.; Kawamoto, F.; Saegusa, T. (1988), "One-Carbon Ring Expansion Of Cycloalkanones To Conjugated Cycloalkenones: 2-Cyclohepten-1-one", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv6p0327 ; Coll. Vol. 6: 327 
  3. ^ a b Roger Adams, C. S. Marvel (1941), "Methylene Iodide", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0358 ; Coll. Vol. 1: 358 

External links

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Look at other dictionaries:

  • diiodomethane — /duy uy euh doh meth ayn/, n. Chem. See methylene iodide. [DI 1 + IODO + METHANE] * * * …   Universalium

  • diiodomethane — noun Methylene iodide, a liquid halomethane used for the separation of minerals and for determining the specific gravity of mineral particles …   Wiktionary

  • diiodomethane — di·io·do·methane …   English syllables

  • diiodomethane — (ˌ)dī|īəˌdō+ noun Etymology: International Scientific Vocabulary diiod + methane : methylene iodide * * * /duy uy euh doh meth ayn/, n. Chem. See methylene iodide. [DI 1 + IODO + METHANE] …   Useful english dictionary

  • Simmons-Smith reaction — The Simmons Smith reaction is an organic reaction in which a carbenoid reacts with an alkene (or alkyne) to form a cyclopropane. [cite journal | author = Howard Ensign Simmons, Jr.; Smith, R.D. | title = 4 Substituted 2,3,5 pyrrolidinetriones |… …   Wikipedia

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  • Industrial radiography — is the use of ionizing radiation to view objects in a way that cannot be seen otherwise. It is not to be confused with the use of ionizing radiation to change or modify objects; radiography s purpose is strictly viewing. Industrial radiography… …   Wikipedia

  • Dibromomethane — IUPAC name …   Wikipedia

  • Diiodmethan — Strukturformel Allgemeines Name Diiodmethan Andere Namen …   Deutsch Wikipedia

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