InChI=1S/C20H18O10S/c1-10(9-29-31(26,27)28)2-3-11-6-12(4-5-14(11)22)20-19(25)18(24)17-15(23)7-13(21)8-16(17)30-20/h2,4-8,21-23,25H,3,9H2,1H3,(H,26,27,28)/b10-2+