ERROR opening https://cactus.nci.nih.gov/chemical/structure/1S/2ClH.Hg/h2%2A1H%3B/q%3B%3B%2B2/p-2/file?format=sdf&get3d=True  -- 1S/2ClH.Hg/h2%2A1H%3B/q%3B%3B%2B2/p-2 could not be loaded.