InChI=1S/C20H19ClO9S/c1-9(8-28-31(25,26)27)4-5-12-10(2)19-16(6-13(12)22)29-15-7-14(23)18(21)11(3)17(15)20(24)30-19/h4,6-7,22-23H,5,8H2,1-3H3,(H,25,26,27)/b9-4+