InChI=1S/C20H20O12S/c21-12-5-3-10(4-6-12)1-2-11-7-13(9-14(8-11)32-33(27,28)29)30-20-17(24)15(22)16(23)18(31-20)19(25)26/h1-9,15-18,20-24H,(H,25,26)(H,27,28,29)/b2-1+