3-[[2-Methoxy-5-methyl-4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]amino]-6-[methyl(2-sulfoethyl)amino]-9-(2-sulfonatophenyl)xanthylium/sodium,(1:x)

dihydrogen -3-[2-methoxy-5-methyl-4-[[2-(sulphonatooxy)ethyl]sulphonyl]anilino]-6-[methyl(2-sulphonatoethyl)amino]-9-(2-sulphonatophenyl)xanthylium , sodium salt