Synonyms: sodium 2-((E)-2-(2-chloro-3-[(E)-2-(1,3,3-trimethyl-5-sulfonato-1,3-dihydro-2h-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl)ethenyl)-1,3,3-trimethyl-3h-indolium-5-sulfonate;3H-indolium, 2-[2-[2-chloro-3-[(1,3-dihydro-1,3,3-trimethyl-5-sulfo-2H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl]ethenyl]-1,3,3-trimethyl-5-sulfo-, inner salt, sodium salt;