ERROR opening https://cactus.nci.nih.gov/chemical/structure/%5BHg%2B%5D.OB%28O%29%5BO-%5D.c1cc%5Bc%5Dcc1/file?format=sdf&get3d=True -- %5BHg%2B%5D.OB%28O%29%5BO-%5D.c1cc%5Bc%5Dcc1 could not be loaded.