Stability and electronic structure of the magnetic hyperhalogen Fe(BF

FeCl4− and BF4− are very stable superhalogen anions, and FeCl4− possesses a magnetic moment of 5 μB due to the singly occupied 3d5 orbitals of the Fe3+. This letter determines the lowest energy structures and stabilities of anionic and neutral Fe(BF4)4−/0 and investigates the magnetic hyperhalogen property by using density function theories and configuration interaction method. The binding and dissociation energies indicate that both the anionic and neutral species are stable. The most stable structure of the anion has D2d symmetry in which the four BF4 units are coordinated to the central Fe atom in bidentate manner. The vertical and adiabatic detachment energies of Fe(BF4)4− reach 10.53 and 9.76 eV, respectively. The 3d orbitals of the central Fe atom form strong covalent bonds with the BF4 units, and the magnetic moments (5 μB) are formed by delocalized spin orbitals