either of two isomeric colourless, dense, water-insoluble liquids belonging to the family of organic halogen compounds. One isomer, 1,1,2,2-tetrachloroethane, also called acetylene tetrachloride, is highly toxic. Almost the entire production of the compound is consumed in manufacturing chlorinated solvents, especially trichloroethylene and tetrachloroethylene; it has minor uses as a solvent and as an insecticide, particularly against the greenhouse white fly. It is made by the reaction of acetylene and chlorine. The other isomer, 1,1,1,2-tetrachloroethane, has no commercial application.