ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1/2CN.Hg/c2*1-2;/rC2HgN2/c4-1-3-2-5/file?format=sdf&get3d=True  -- InChI=1/2CN.Hg/c2*1-2;/rC2HgN2/c4-1-3-2-5 could not be loaded.