2-[3-[[2,3-Dihydro-1-methyl-3-[4-(sodiosulfo)butyl]-5-(trifluoromethyl)-1H-benzimidazol]-2-ylidene]-1-propenyl]-1-methyl-3-(4-sulfonatobutyl)-5-(trifluoromethyl)-1H-benzimidazol-3-ium

1H-Benzimidazolium, 2-[3-[1,3-dihydro-1-methyl-3-(4-sulfobutyl)-5-(trifluoromethyl)-2H-benzimidazol-2-ylidene]-1-propenyl]-1-methyl-3-(4-sulfobutyl)-5-(trifluoromethyl)-, hydroxide, inner salt, sodium salt