InChI=1S/C18H12O11S/c19-11-6-10-7-16(18(23)28-14(10)8-12(11)20)27-13-3-1-9(2-4-17(21)22)5-15(13)29-30(24,25)26/h1-8,19-20H,(H,21,22)(H,24,25,26)/b4-2+