InChI=1S/C16H16O11S/c17-10-3-1-8(5-13(10)27-28(23,24)25)2-4-14(20)26-15-11(18)6-9(16(21)22)7-12(15)19/h1-6,11-12,15,17-19H,7H2,(H,21,22)(H,23,24,25)/b4-2+