InChI=1S/C16H16O9S/c17-7-9-6-5-8(26-9)3-1-2-4-10(18)24-16-13(21)11(19)12(20)14(25-16)15(22)23/h2,4-6,11-14,16-17,19-21H,7H2,(H,22,23)/b4-2+