InChI=1S/C20H16O9S/c1-10(9-27-30(24,25)26)2-3-11-6-14-17(8-15(11)22)29-20(23)18-13-5-4-12(21)7-16(13)28-19(14)18/h2,4-8,21-22H,3,9H2,1H3,(H,24,25,26)/b10-2+