4-[[5-[[4-chloro-6-[(4-sulphophenyl)amino]-1,3,5-triazin-2-yl]amino]-2-sulphophenyl]azo]-4,5-dihydro-5-oxo-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid, sodium salt

4-[[5-[[4-Chloro-6-[(4-sulfophenyl)amino]-1,3,5-triazine-2-yl]amino]-2-sulfophenyl]azo]-4,5-dihydro-5-oxo-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylic acid/sodium,(1:x) salt