InChI=1S/C16H12N2O8S2/c19-13-7-5-12-11(6-8-14(16(12)20)28(24,25)26)15(13)18-17-9-1-3-10(4-2-9)27(21,22)23/h1-8,19-20H,(H,21,22,23)(H,24,25,26)/b18-17+