InChI=1S/C21H18O12/c22-10(13-11(23)7-12(24)14(25)15(13)26)6-3-8-1-4-9(5-2-8)32-21-18(29)16(27)17(28)19(33-21)20(30)31/h1-7,16-19,21,24,26-29H,(H,30,31)/b6-3+