ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/CH4N2Se/c2-1%283%294/h%28H4%2C2%2C3%2C4%29/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/CH4N2Se/c2-1%283%294/h%28H4%2C2%2C3%2C4%29 could not be loaded.