InChI=1S/C21H20O9/c1-9-17(25)18(26)19(27)21(28-9)30-16-8-13-14(24)6-12(23)7-15(13)29-20(16)10-2-4-11(22)5-3-10/h2-9,17-19,21,25-27H,1H3,(H2-,22,23,24)/p+1