THE CHEMISTRY OF THE SUPERHEAVY ELEMENTS - II - THE STABILITY OF HIGHOXIDATION-STATES IN GROUP-11 ELEMENTS - RELATIVISTIC COUPLED-CLUSTER CALCULATIONS FOR THE DIFLUORO, TETRAFLUORO AND HEXAFLUORO METALLATES OF CU, AG, AU, AND ELEMENT-111

The stability of the high oxidation states +3 and +5 in Group 11 fluor ides is studied by relativistic Moller-Plesset (MP) and coupled cluste r methods. Higher metal oxidation states are stabilized by relativisti c effects. As a result, the hexafluoro complex of the Group 11 element with nuclear charge 111 and oxidation state +5 is the most stable com pared to the other congeners. The results also suggest that AgF6- is t hermodynamically stable and, therefore, it might be feasable to synthe size this compound. For the copper fluorides we observe very large osc illations in the Moller-Plesset series up to the fourth order. Nonrela tivistic calculations lead to the expected trend in the metal-fluorine bond distances for the MF2- compounds, CuF2- < AgF2- < AuF2- < (111)F -2(-). However, relativistic effects change this trend to CuF2- < AuF2 - < (111)F-2(-) < AgF2-. Vibrational frequencies are predicted for all compounds. Where experimental data are available, they generally agre e very well with our calculated results. (C) 1998 American Institute o f Physics. [S0021-9606(98)30334-7].