InChI=1S/C19H16O11S/c1-28-19(24)17(10-12-2-5-13(20)14(21)8-12)29-15-6-3-11(4-7-18(22)23)9-16(15)30-31(25,26)27/h2-10,20-21H,1H3,(H,22,23)(H,25,26,27)/b7-4+,17-10-