N-[4-[4-Diethylaminophenyl[3-(sulfonatomethyl)-4-(sodiosulfomethyl)phenyl]methylene]-2,5-cyclohexadien-1-ylidene]-N-ethylethanaminium

hydrogen [4-[4-(diethylamino)-3',4'-bis(sulphonatomethyl)benzhydrylidene]cyclohexa-2,5-dien-1-ylidene]diethylammonium, monosodium salt