ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%26%2361%3B1S/3Mg.2N/q3%2A%2B2%26%2359%3B2%2A-3/file?format=sdf&get3d=True  -- InChI%3DInChI%26%2361%3B1S/3Mg.2N/q3%2A%2B2%26%2359%3B2%2A-3 could not be loaded.