ERROR opening https://cactus.nci.nih.gov/chemical/structure/C%3D%5BCH-%5D.%5BMg%2B2%5D.%5BBr-%5D/file?format=sdf&get3d=True -- C%3D%5BCH-%5D.%5BMg%2B2%5D.%5BBr-%5D could not be loaded.