ERROR opening https://cactus.nci.nih.gov/chemical/structure/O.O.%5BMg%202%5D.%5BO-%5DCl%28%3DO%29%3DO.%5BO-%5DCl%28%3DO%29%3DO/file?format=sdf&get3d=True  -- O.O.%5BMg%202%5D.%5BO-%5DCl%28%3DO%29%3DO.%5BO-%5DCl%28%3DO%29%3DO could not be loaded.