trisodium 1-(5-amino-2-methyl-3-sulphonatophenyl)-4,5-dihydro-5-oxo-4-[(2-sulphonatophenyl)azo]-1H-pyrazole-3-carboxylate

1-[5-Amino-2-methyl-3-(sodiosulfo)phenyl]-4,5-dihydro-5-oxo-4-[2-(sodiosulfo)phenylazo]-1H-pyrazole-3-carboxylic acid sodium salt