InChI=1S/C20H20O10S/c1-10(9-29-31(26,27)28)2-4-13-15(23)7-18-19(20(13)25)16(24)8-17(30-18)12-5-3-11(21)6-14(12)22/h2-3,5-7,17,21-23,25H,4,8-9H2,1H3,(H,26,27,28)/b10-2+