5-Methyl-2-[2-methyl-3-[5-methyl-3-(3-sodiosulfopropyl)benzothiazol-2(3H)-ylidene]-1-propenyl]-3-(3-sulfonatopropyl)benzothiazolium

hydrogen 5-methyl-2-[2-methyl-3-[5-methyl-3-(3-sulphonatopropyl)-3H-benzothiazol-2-ylidene]prop-1-enyl]-3-(3-sulphonatopropyl)benzothiazolium, sodium salt