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