ERROR opening https://cactus.nci.nih.gov/chemical/structure/O.O.O.O%3D%5BU%2B2%5D%3DO.%5BCl-%5D.%5BCl-%5D/file?format=sdf&get3d=True  -- O.O.O.O%3D%5BU%2B2%5D%3DO.%5BCl-%5D.%5BCl-%5D could not be loaded.