Chemistry:Tetrahalomethane

Tetrahalomethanes are chemical compounds in which all four hydrogen atoms of a methane molecule are replaced by halogen atoms—such as chlorine, bromine, fluorine, iodine, or astatine.

Overview

The compounds are fully halogenated methane derivatives of general formula CF_kCl_lBr_mI_nAt_p, where:$$k+l+m+n+p=4$$Tetrahalomethanes are on the border of inorganic and organic chemistry, thus they can be assigned both inorganic and organic names by IUPAC: tetrafluoromethane - carbon tetrafluoride, tetraiodomethane - carbon tetraiodide, dichlorodifluoromethane - carbon dichloride difluoride.

Taxonomy

Each halogen (F, Cl, Br, I, At) forms a corresponding halomethane, but their stability decreases in order CF₄ > CCl₄ > CBr₄ > CI₄ from exceptionally stable gaseous tetrafluoromethane with bond energy 515 kJ·mol⁻¹ to solid tetraiodomethane, depending on bond energy.

Many mixed halomethanes are also known, such as CBrClF₂.

Uses

Fluorine, chlorine, and sometimes bromine-substituted halomethanes were used as refrigerants, commonly known as CFCs (chlorofluorocarbons).

See also

• Monohalomethane
• Dihalomethane
• Trihalomethane