Relativistically parameterized extended Hueckel calculations. 3. Structure and bonding for some compounds of uranium and other heavy elements

The relativistically parameterized extended Hueckel molecular orbital method REX is used to explore the effects of relativity upon molecular orbital energies and compositions. The uranium compounds studied are UO22+, UO2Cl42-, UF6, UCl6, UCl4, U(BH4)4, and U(C8H8)2. Other heavy element compounds studied are MI3 (M = La, Gd, Lu), PoH2, (eka)PoH2, I3-, AtI2-, and RnF2. Relativistic orbital energy parameters and atomic orbital exponents are presented as supplementary material for all elements with Z = 1 to 120 together with corresponding nonrelativistic values for all elements with Z = 1 to 100. It is concluded that the REX method provides semiquantitative estimates of spin-orbit splittings and relativistic bonding effects for compounds of heavy elements