There are three distinct chemical compounds which are dichlorobenzenes:
1,2-Dichlorobenzene or ortho-dichlorobenzene; 1,3-Dichlorobenzene or meta-dichlorobenzene; 1,4-Dichlorobenzene or para-dichlorobenzene. All three isomers are colorless chlorobenzenes with the formula C6H4Cl2. They differ structurally based on where the two chlorine atoms are attached to the ring.
See also Dibromobenzene
References