ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/2C5H5.Mg/c2*1-2-4-5-3-1;/h2*1-5H/file?format=sdf&get3d=True  -- InChI=1S/2C5H5.Mg/c2*1-2-4-5-3-1;/h2*1-5H could not be loaded.