Synonyms: Cuprate(4-), (mu-((7,7'-((3,3'-di(hydroxy-kappaO)(1,1'-biphenyl)-4,4'-diyl)bis(2,1-diazenediyl-kappaN1))bis(8-(hydroxy-kappaO)-1,6-naphthalenedisulfonato))(8-)))di-, sodium (1:4);Cuprate(4-), (mu-((7,7'-((3,3'-di(hydroxy-kappaO)(1,1'-biphenyl)-4,4'-diyl)bis(azo-kappaN1))bis(8-(hydroxy-kappaO)-1,6-naphthalenedisulfonato))(8-)))di-, tetrasodium;Tetrasodium (mu-((7,7'-((3,3'-dihydroxy(1,1'-biphenyl)-4,4'-diyl)bis(azo))bis(8-hydroxynaphthalene-1,6-disulphonato))(8-)))dicuprate(4-);copper(2+) sodium 7,7'-[(3,3'-dioxidobiphenyl-4,4'-diyl)di(E)diazene-2,1-diyl]bis(8-oxidonaphthalene-1,6-disulfonate) (2:4:1)