SMILES: C1=CC=C(C(=C1)N=NC2=CC=CC=C2S(=O)(=O)O)S(=O)(=O)O
Description: The molecule is azobenzene substituted at C-2 of each phenyl group by a sulfo group. It is a member of azobenzenes and an arenesulfonic acid. It is a conjugate acid of a 2,2'-disulfonatoazobenzene.