C.I. 22610; C.I. Direct Blue 6; C.I. Direct Blue 6, tetrasodium salt; C.I. Direct Blue 6, tetrasodium salt; (3Z)-5-amino-3-({4'-[(2E)-2-(8-amino-1-oxo-3,6-disulfonaphthalen-2(1H)-ylidene)hydrazino]biphenyl-4-yl}hydrazono)-4-oxo-3,4-dihydronaphthalene-2,7-disulfonic acid; tetrasodium (3Z)-5-amino-3-({4'-[(2E)-2-(8-amino-1-oxo-3,6-disulfonatonaphthalen-2(1H)-ylidene)hydrazino]biphenyl-4-yl}hydrazono)-4-oxo-3,4-dihydronaphthalene-2,7-disulfonate; tetrasodium (3Z,3'Z)-3,3'-[biphenyl-4,4'-diyldi(1Z)hydrazin-2-yl-1-ylidene]bis(5-amino-4-oxo-3,4-dihydronaphthalene-2,7-disulfonate)