2-[5-[1,3-Dihydro-3,3-dimethyl-5-sulfo-1-(3-sulfopropyl)-2H-indol-2-ylidene]-1,3-pentadienyl]-3,3-dimethyl-5-sulfo-1-(3-sulfopropyl)-3H-indolium inner salt trisodium salt
2-[5-[1,3-Dihydro-3,3-dimethyl-5-sulfo-1-(3-sulfopropyl)-2H-indol-2-ylidene]-1,3-pentadienyl]-3,3-dimethyl-5-sulfo-1-(3-sulfopropyl)-3H-indolium inner salt trisodium salt