InChI=1S/C18H14O8/c19-13-7-9(1-3-15(21)22)5-11(17(13)25)12-6-10(2-4-16(23)24)8-14(20)18(12)26/h1-8,19-20,25-26H,(H,21,22)(H,23,24)/b3-1+,4-2+