ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/4C2H4O2.2O.U.Zn/c4*1-2(3)4;;;;/h4*1H3,(H,3,4);;;;/q;;;;;;2* 2/p-4/file?format=sdf&get3d=True  -- InChI=1S/4C2H4O2.2O.U.Zn/c4*1-2(3)4;;;;/h4*1H3,(H,3,4);;;;/q;;;;;;2* 2/p-4 could not be loaded.