EINECS 218-145-5, EINECS 288-526-9, Benzenesulfonic acid,3-((1,5-dihydroxy-2-naphthalenyl)azo)-4-hydroxy-,sodium salt, Benzenesulfonic acid,3-((1,5-dihydroxy-2-naphthalenyl)azo)-4-hydroxy-,monosodium salt, Sodium 3-((1,5-dihydroxy-2-naphthyl)azo)-4-hydroxybenzenesulphonate, C.I. Mordant Black 9,monosodium salt