sodium 9,10-dioxoanthracene-2,6-disulfonic acid sodiumanthraquinone-2,6(2,7)-disulfonate 6-disulfonic acid disodiuM salt anthraquinone-2,6-disulphonicaciddisodiumsalt 9,10-Dioxo-9,10-dihydro-2,6-anthracenedisulfonic acid disodium salt 9,10-Dioxo-9,10-dihydroanthracene-2,6-bis(sulfonic acid sodium) salt 9,10-Dioxoanthracene-2,6-disulfonic acid disodium salt Disodium 9,10-dioxo-9,10-dihydro-2,6-anthracenedisulfonate