2-Naphthalenesulfonic acid, 7,7'-(carbonyldiimino)bis(4-hydroxy-, monosodium salt 7,7'-Ureylenebis(4-hydroxy-2-naphthalenesulfonic acid), monosodium salt 71550-28-2 EINECS 275-605-8 Sodium hydrogen 7,7'-(carbonyldiimino)bis(4-hydroxynaphthalene-2-sulphonate)