ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C2.6CH3.2Pb/c1-2;;;;;;;;/h;6*1H3;;/file?format=sdf&get3d=True  -- InChI=1S/C2.6CH3.2Pb/c1-2;;;;;;;;/h;6*1H3;; could not be loaded.