Volatility of molecules

Volatility studies of various volatile halides, oxyhalides and/or oxides has been the subject of an extensive experimental research fi om 1969 on when Zvara et al. performed first experiments with RfCU [45,196-198]. Since then, volatility studies were performed for group-4 and -5 chlorides, bromides and oxychlorides, group-6 and -7 oxychlorides and group-8 oxides. The experiments have established a number of trends in volatilities of the heaviest element compounds, while they have also revealed a number of controversies. Results of 

Contributions to the interaction energy E(xJ between neutral MO3CI molecules (M = Tc, Re, 

Experimental investigations of volatilities of group-4 through 7 species were mostly performed with the use of the isothermal chromatography column. For 

A Monte Carlo program was used to deduce AHads of -75 kJ/mol with a 68% confidence interval for BhOsCl, the most probable oxychloride imder these conditions. The values for the Tc and Re oxychlorides studied imder the same conditions are -51 kJ/mol and -61 kJ/mol, respectively. Thus, BhOsCl shows a stronger adsorption interaction with the chlorinated quartz surface than either of TcOsCl or ReOsCl, and is more similar to Re than to Tc. The obtained AHads are in very good agreement with the calculations described above [144]. Thus, a volatility sequence of TCO3CI ReOsCl BhOsCl was observed in agreement 

Influence of relativistic effects on the volatility of the heaviest element compounds can not be established in a straightforward way by these measurements. Qualitatively, one can probably state the following. The p and a, as well as the molecular size, are decreased by relativistic effects. The IP and covalence, in turn, are relativistically increased. Since all these quantities contribute to the molecule-surface interaction energy, volatility should, therefore, increase as a result of relativity. Quantitatively, such effects could, however, be obtained only by comparing experimental behaviour with that predicted on the basis of relativistic versus nonrelativistic calculations. 

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