Tetrahalomethanes are fully halogenated methane derivatives of general formula CBrkCllFmIn.
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.
Each halogen (F, Cl, Br, I) forms corresponding halomethane, but their stability decreases in order CF4 > CH4 > CCl4 > CBr4 > CI4 from exceptionally stable gaseous tetrafluoromethane with bond energy 515 kJ.mol−1 to solid tetraiodomethane. It depends on bond energy.
Many mixed halomethanes are also known, such as CBrClF2.
Uses
Fluorine and chlorine, sometimes bromine-substituted halomethanes are used as refrigerants.