InChI=1S/C20H14N2O7S2/c23-18-9-5-12-11-13(30(24,25)26)6-7-14(12)20(18)22-21-17-8-10-19(31(27,28)29)16-4-2-1-3-15(16)17/h1-11,23H,(H,24,25,26)(H,27,28,29)/b22-21+