[Er].O=C(CC(=O)C(F)(F)C(F)(F)C(F)(F)F)C(C)(C)C.O=C(CC(=O)C(F)(F)C(F)(F)C(F)(F)F)C(C)(C)C.O=C(CC(=O)C(F)(F)C(F)(F)C(F)(F)F)C(C)(C)C