Compounds of superheavy elements

Superheavy elements are those with Z 104 (transactinides). One may distinguish the d elements (Z=104-112) and the superheavy Ip elements (Z=113-118). Considerable progress has been made in the production of such elements. Element 104-106 have isotopes which are stable enough to perform chemical experiments [141, 142], while for elements such as element 114, both the production rate and the lifetimes are too small to allow for experimental chemical investigations. Besides experiments, relativistic density functional calculations have been performed for compounds of the 6d elements. A detailed account can be found in chapter 1 of this volume. 

Here we will concentrate on the heavy congeners of the elements discussed so far, namely element 111 (eka-gold) and elements 113 through 115 (eka-thallium, eka-lead and eka-bismuth). There are two motivations for performing relativistic density functional calculations on compounds of these elements. First, computational results are the only source of information on chemical properties of these elements. These properties show how the periodic table of the elements extends to the lower edge. Second, it is interesting to compare results from 

A small spin-orbit Cl using configurations from scalar-relativistic calculations cannot describe the large relaxation from the scalar-relativistic to the spin-orbit coupled orbitals. Methods that use two-component orbitals from the start show much faster convergence of the Cl expansion. 

Relativistic molecular density functional calculations, as performed today, essentially use results from non-relativistic density functional theory combined with the Dirac (four-component) form of the one-particle equations. In other words, the motion of the electron is treated relativistically but the interaction between particles is still described by the non-relativistic expressions. 

Density functional results for some compounds of elements 113,114 and 115 

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Besides the elemental state, also volatile compounds of superheavy elements have been considered. K. Bachmann et al. [107] extrapolated the boiling points of hydrides, methyl- and ethyl compounds of elements 113 through 117. N. Trautmann et al. [108] showed, that short-lived 216Po (T1/2 = 0.15 s) was volatilized using ethyl radicals, probably as diethylpolonium. 

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