The dihalomethanes are organic compounds in which two hydrogen atoms in

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...

are replaced by halogen atoms. They belong to the

haloalkanes The haloalkanes (also known as halogenoalkanes or alkyl halides) are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely us ...

, specifically the subgroup of

halomethanes Halomethane compounds are derivatives of methane () with one or more of the hydrogen atoms replaced with halogen atoms ( F, Cl, Br, or I). Halomethanes are both naturally occurring, especially in marine environments, and human-made, most notably ...

, and contains ten members. There are four members with only one kind of halogen atom:

difluoromethane Difluoromethane, also called difluoromethylene, HFC-32 Methylene Fluoride or R-32, is an organic compound of the dihalogenoalkane variety. It has the formula of CH2F2. It is a colorless gas in the ambient atmosphere and is slightly soluble in th ...

, dichloromethane,

dibromomethane Preparation Dibromomethane is prepared commercially from dichloromethane via bromochloromethane: :6 CH2Cl2 + 3 Br2 + 2 Al → 6 CH2BrCl + 2 AlCl3 :CH2Cl2 + HBr → CH2BrCl + HCl The latter route requires aluminium trichloride as a catal ...

and

diiodomethane 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 solub ...

. There are six members with two kinds of halogen atoms: *

Bromochloromethane Bromochloromethane or methylene bromochloride and Halon 1011 is a mixed halomethane. It is a heavy low-viscosity liquid with refractive index 1.4808. Halon 1011 was invented for use in fire extinguishers in Germany during the mid-1940s, in an att ...

* Bromofluoromethane *

Bromoiodomethane Bromoiodomethane is a halomethane with the formula BrCH2I. It is a colorless liquid, although older samples appear yellow. The compound has been investigated as a reagent for cyclopropanation by the Simmons-Smith reaction, but diiodomethane and ...

Chlorofluoromethane Chlorofluoromethane or Freon 31 is the hydrochlorofluorocarbon (HCFC) with the formula CH2ClF. It is a colorless, odorless, flammable gas. Uses Pyrolysis of a mixture of dichlorofluoromethane and chlorofluoromethane gives hexafluorobenzene: :3 C ...

Chloroiodomethane Chloroiodomethane is the halomethane with the formula is . It is a colorless liquid of use in organic synthesis. Together with other iodomethanes, chloroiodomethane is produced by some microorganisms. Applications Chloroiodomethane is used in c ...

* Fluoroiodomethane

See also