Synonyms: Cuprate(4-),[m-[[3,3'-[(3,3'-dihydroxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[4,5-dihydroxy-2,7-naphthalenedisulfonato]](8-)]]di-,tetrahydrogen; 2,7-Naphthalenedisulfonic acid,3,3'-[(3,3'-dihydroxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[4,5-dihydroxy-,copper complex