Appearance: Black to dark brown-black fine powder, eventually with granular parts
Clarity of solution: passes test
Absorption maximum λmax. (buffer pH 10.0): 612 – 616 nm
Spec. Absorptivity A 1%/1cm (λmax; 0.02 g/l; buffer pH 10.0; calc. on dried substance): 400 – 510
Loss on drying (110 °C): ≤ 7 %
Suitability as indicator (for complexometric titration, ACS): passes test
Suitability as indicator (Reag. Ph Eur): passes test