C.I. Food Black 2; CI 27755; tetrasodium (3E)-6-amino-4-oxo-3-(2-{7-sulfinato-4-[(E)-(4-sulfonatophenyl)diazenyl]naphthalen-1-yl}hydrazinylidene)-3,4-dihydronaphthalene-2,7-disulfonate; tetrasodium 6-amino-4-hydroxy-3-[[7-sulfonato-4-(4-sulfonatophenyl)azo-1-naphthyl]azo]naphthalene-2,7-disulfonate