ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/C4GeN4/c6-1-5%282-7%2C3-8%294-9/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/C4GeN4/c6-1-5%282-7%2C3-8%294-9 could not be loaded.