ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%5BHg%5DCC%28OC%29CNC%28%3DO%29c1ccccc1OCC%28O%29%3DO/file?format=sdf&get3d=True -- O%5BHg%5DCC%28OC%29CNC%28%3DO%29c1ccccc1OCC%28O%29%3DO could not be loaded.