ERROR opening https://cactus.nci.nih.gov/chemical/structure/%5BFe%2B2%5D.%5BO-%5DC%28%3DO%29/C%3DC/C%28%5BO-%5D%29%3DO/file?format=sdf&get3d=True -- %5BFe%2B2%5D.%5BO-%5DC%28%3DO%29/C%3DC/C%28%5BO-%5D%29%3DO could not be loaded.