4-[(5-Amino-2-sulfophenyl)azo]-4,5-dihydro-5-oxo-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylic acid

4-[(5-amino-2-sulphophenyl)azo]-4,5-dihydro-5-oxo-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid