3-[(4,5-dihydro-5-oxo-1,3-diphenyl-1H-pyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulphonic acid

3-[[(4,5-Dihydro-5-oxo-1,3-diphenyl-1H-pyrazol)-4-yl]azo]-2-hydroxy-5-nitrobenzenesulfonic acid