1,4-Dichlorobenzene (p-DCB or para-dichlorobenzene, sometimes abbreviated as PDB or para) is an organic compound with the formula C6H4Cl2. This colorless solid has a strong odor. The molecule consists of a benzene ring with two chlorine atoms (replacing hydrogen atoms) on opposing sites of the ring. It is used as a pesticide and a deodorant, most familiarly in mothballs in which it is a replacement for the more traditional naphthalene because of its flammability (though both chemicals have the same NFPA 704 rating). It is also used as a precursor in the production of the polymer poly(p-phenylene sulfide).