InChI=1S/C15H14O12S/c1-8(16)25-12(14(18)19)13(15(20)21)26-11(17)7-4-9-2-5-10(6-3-9)27-28(22,23)24/h2-7,12-13H,1H3,(H,18,19)(H,20,21)(H,22,23,24)/b7-4+