When does gold behave as a halogen? Predicted uranium tetraauride and other MAu4 tetrahedral species, (M = Ti, Zr, Hf, Th).
Quantum chemical calculations suggest that a series of molecules with the general formula MAu4 are stable, where M = U, Th, and a group-4 atom. They correspond to Au in the formal valence state -1 and indicate that gold can act as a ligand similar to the halogen series. Of the MAu4 species studied, UAu4, the first predicted mixed gold uranium compound, has a short M-Au bond distance, 2.71 A, which would locate Au between Br and I from the bond length point of view in the U-tetrahalide series. Energetically, the U-Au bond is weaker than the corresponding U-Br and U-I bonds.
Gagliardi
Laura
L
Department of Physical Chemistry, Viale delle Scienze Parco d'Orleans II, University of Palermo, 90128 Palermo, Italy. laurag@clam.unibo.it