Synonyms: 2,7-Naphthalenedisulfonic acid, 3,3'-((1-oxido-1,2-diazenediyl)bis((2-methoxy-4,1-phenylene)-2,1-diazenediyl))bis(4,5-dihydroxy-;2,7-Naphthalenedisulfonic acid, 3,3'-(azoxybis((2-methoxy-4,1-phenylene)azo))bis(4,5-dihydroxy-;3,3'-(Azoxybis((2-methoxy-4,1-phenylene)azo))bis(4,5-dihydroxynaphthalene-2,7-disulphonic) acid;(3Z)-5-hydroxy-3-(2-{4-[(2E)-1-hydroxy-2-{(4Z)-4-[(2E)-(8-hydroxy-1-oxo-3,6-disulfonaphthalen-2(1H)-ylidene)hydrazinylidene]-3-methoxycyclohexa-2,5-dien-1-ylidene}hydrazinyl]-2-methoxyphenyl}hydrazinylidene)-4-oxo-3,4-dihydronaphthalene-2,7-disulfonic acid