Bis[1-[(2-ethyl-6-nitrophenyl)azo]-2-hydroxy-8-naphthalenesulfonic acid]barium salt C??? ??, ??, ??

Bis[1-[(2-ethyl-6-nitrophenyl)azo]-2-hydroxy-8-naphthalenesulfonic acid]barium salt ?? ?? ? ???

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Bis[1-[(2-ethyl-6-nitrophenyl)azo]-2-hydroxy-8-naphthalenesulfonic acid]barium salt ?? ??