ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/4CN.2K.Zn/c4*1-2;;;/q4*-1;2*+1;+2/file?format=sdf&get3d=True -- InChI=1S/4CN.2K.Zn/c4*1-2;;;/q4*-1;2*+1;+2 could not be loaded.