ERROR opening https://cactus.nci.nih.gov/chemical/structure/%5BSi%5D%28%3D%5BNi%5D%29%3D%5BNi%5D/file?format=sdf&get3d=True  -- %5BSi%5D%28%3D%5BNi%5D%29%3D%5BNi%5D could not be loaded.