ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/2C8H8.U/c2%2A1-2-4-6-8-7-5-3-1/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/2C8H8.U/c2%2A1-2-4-6-8-7-5-3-1 could not be loaded.