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