C₆H₄Cl₂ Any of a group of substitution products of benzene and two atoms of chlorine; the three forms are meta-dichlorobenzene, colorless liquid boiling at 172_C, soluble in alcohol and ether, insoluble in water, or ortho-, colorless liquid boiling at 179_C, used as a solvent and chemical intermediate, or para-, volatile white crystals, insoluble in water, soluble in organic solvents, used as a germicide, insecticide, and chemical intermediate.