ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%26%2361%3B1S/C2H2/c1-2/h1-2H/file?format=sdf&get3d=True  -- InChI%3DInChI%26%2361%3B1S/C2H2/c1-2/h1-2H could not be loaded.