The chemistry of superheavy elements. III. Theoretical studies on element 113 compounds

The chemistry of element 113 is investigated by theoretical methods. The re sults of fully relativistic calculations for (113)H and (113)F are compared with those derived by other techniques to obtain an indication of the accu racy of the more approximate models as well as the importance of including scalar and/or spin-orbit relativistic effects. Both of these effects are fo und to be important. The spin-orbit coupled pseudopotential approximation y ields results of satisfactory accuracy, but the two relativistic methods th at do not include spin-orbit coupling (Douglas-Kroll and scalar relativisti c pseudopotential method) do not agree so well with each other. The calcula ted properties of (113)H and (113)F and a number of other hydrides and hali des of element 113 are compared with the properties of the equivalent compo unds of the lighter group 13 elements. In general, element 13 exhibits beha vior that is consistent with its placement in group 13 of the periodic tabl e. Some of its properties are found to be somewhat unusual however, e.g., t he element is relatively electronegative, the molecules (113)H-3, (113)F-3, and (113)Cl-3 are predicted to be T-shaped rather than trigonal planar, an d the 6d electrons of element 113 participate to a significant extent in ch emical bonding. Compounds where element 113 is present in the +5 oxidation state are considered as well but are predicted to be thermodynamically unst able. (C) 1999 American Institute of Physics. [S0021-9606(99)30738-8].