InChI=1S/C18H18O13/c19-9(30-14(16(25)26)17(27)28)6-3-7-1-4-8(5-2-7)29-18-12(22)10(20)11(21)13(31-18)15(23)24/h1-6,10-14,18,20-22H,(H,23,24)(H,25,26)(H,27,28)/b6-3+