InChI=1S/C15H18O12S/c16-6-10-12(19)13(20)14(21)15(26-10)25-8-3-1-7(2-4-11(17)18)5-9(8)27-28(22,23)24/h1-5,10,12-16,19-21H,6H2,(H,17,18)(H,22,23,24)/b4-2+