The molecule is an arenesulfonic acid that is 5,6-dihydronaphthalene-2-sulfonic acid bearing hydroxyimino and oxo substituents at positions 5 and 6 respectively. The trisodium-iron(3+) salt is the biological stain 'naphthol green B'. It is an arenesulfonic acid, a ketoxime and a naphthalenone. It is a conjugate acid of a 5-(oxidoimino)-6-oxo-5,6-dihydronaphthalene-2-sulfonate.
6-hydroxy-5-nitrosonaphthalene-2-sulfonic acid