The molecule is an organosulfonate oxoanion obtained by deprotonation of the sulfo groups of 7-hydroxy-8-{[4-(phenyldiazenyl)phenyl]diazenyl}naphthalene-1,3-disulfonic acid. It is a conjugate base of a 7-hydroxy-8-{[4-(phenyldiazenyl)phenyl]diazenyl}naphthalene-1,3-disulfonic acid.
7-hydroxy-8-[(4-phenyldiazenylphenyl)diazenyl]naphthalene-1,3-disulfonate