ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%26%2361%3BS1%28%26%2361%3BO%29O%26%2391%3BHg%26%2393%3BO1/file?format=sdf&get3d=True -- O%26%2361%3BS1%28%26%2361%3BO%29O%26%2391%3BHg%26%2393%3BO1 could not be loaded.