Gas phase chemistry studies of transactinoid elements and the relativisticeffects

Fast techniques based on gas-solid chromatography have played a major role in the experimental studies of transactinoid (Z >103) nuclides, which all p ossess half-lives less than a minute. To date, elements 104 to 106, the tra nsition metals of groups 4 to 6, have been chemically identified, and their (oxo)halides have been studied. The most challenging problem in transactin oids is the "relativistic effects in chemical properties": the properties o f new elements might not closely follow the trends observed for the lighter congeners in the appropriate groups, because at such high Z's atomic elect rons reach relativistic velocities. Generally, one must first "translate" t he experimental data obtained with single atoms (molecules, ions) into the macroscopic characteristics like the boiling point, vaporization enthalpy, etc. Before considering the relativistic effects, one has to exclude the tr ivial origin of the differences (if any) from the properties of the congene rs to identify the really unexpected deviations. Then some inorganic chemis try theories, empirical regularities and results of sophisticated relativis tic calculations of atoms and molecules (ions) are to be consulted in an at tempt to predict the difference between the "nonrelativistic" and "relativi stic" values of the above quantities. The problem is analyzed with the vola tility of tetrachloride of element 104 as an example.