Synonyms: Cuprate(2-), (mu-((3,3'-(methylenebis((4-(hydroxy-kappaO)-6-hydroxy-3,1-phenylene)-2,1-diazenediyl-kappaN1))bis(4-(hydroxy-kappaO)-5-nitrobenzenesulfonato))(6-)))di-, sodium;Cuprate(2-), (mu-((3,3'-(methylenebis((4,6-dihydroxy-3,1-phenylene)azo))bis(4-hydroxy-5-nitrobenzenesulfonato))(6-)))di-, sodium