Synonyms: Cuprate(4-),[m-[[3,3'-[(3,3'-dihydroxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[4-hydroxy-6-[(3-sulfophenyl)amino]-2-naphthalenesulfonato]](8-)]]di-,tetrasodium (9CI); 2-Naphthalenesulfonic acid, 3,3'-[(3,3'-dihydroxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[4-hydroxy-6-[(3-sulfophenyl)amino]-,copper complex