The molecule is a naphthalenesulfonic acid that is naphthalene-2,7-disulfonic acid carrying two additional hydroxy substituents at positions 4 and 5 as well as a phenyldiazenyl substituent at position 3. The disodium salt is the biological stain 'acid red 29'. It is a member of azobenzenes, a naphthalenesulfonic acid and a member of naphthalenediols. It is a conjugate acid of a 4,5-dihydroxy-3-(phenyldiazenyl)naphthalene-2,7-disulfonate.
4,5-dihydroxy-3-phenyldiazenylnaphthalene-2,7-disulfonic acid