N-[4-[[4-(Dimethylamino)-3-sodiosulfophenyl][2-ethoxy-4-[(4-methyl-2-sodiosulfophenyl)amino]phenyl]methylene]-2-sulfonato-2,5-cyclohexadien-1-ylidene]-N-methylmethanaminium

dihydrogen [4-[[4-(dimethylamino)-3-sulphonatophenyl][2-ethoxy-4-(2-sulphonato-p-toluidino)phenyl]methylene]-2-sulphonatocyclohexa-2,5-dien-1-ylidene]dimethylammonium, disodium salt