InChI=1S/C18H16O11S/c19-12-4-2-11(7-14(12)21)9-16(18(23)24)28-17(22)6-3-10-1-5-13(20)15(8-10)29-30(25,26)27/h1-8,16,19-21H,9H2,(H,23,24)(H,25,26,27)/b6-3+