InChI=1S/C20H20O10S/c1-8(21)20(26)6-5-9-11(7-20)18(24)14-15(16(9)22)19(25)13-10(17(14)23)3-2-4-12(13)30-31(27,28)29/h2-4,8,21-22,24,26-29H,5-7H2,1H3/p-2/t8?,20-/m1/s1