ERROR opening https://cactus.nci.nih.gov/chemical/structure/C1%3DCC%3DC-C%3DC1.C1%3DCC%3DC-C%3DC1.Zn%202/file?format=sdf&get3d=True  -- C1%3DCC%3DC-C%3DC1.C1%3DCC%3DC-C%3DC1.Zn%202 could not be loaded.