InChI=1S/C18H12O12S/c19-9-3-1-7(2-4-9)13(17(23)24)16-14(22)12(18(25)29-16)8-5-10(20)15(11(21)6-8)30-31(26,27)28/h1-6,12,19-21H,(H,23,24)(H,26,27,28)/b16-13-