Sulfonazo III [Spectrophotometric reagent for alkaline earth metals and indicator for the precipitation titration of SO4 with Ba]

C1=CC=C (C (=C1) N=NC2=C (C3=C (C (=C (C=C3C=C2S (=O) (=O) [O-]) S (=O) (=O) [O-]) N=NC4=CC=CC=C4S (=O) (=O) [O-]) O) O) S (=O) (=O) [O-].[Na+].[Na+].[Na+].[Na+]