Volatility of atoms

Element 103. One of the first experiments testing relativistic effects in the heaviest element region was that on the volatility of atomic Lr [185]. The sublimation energy of Lr in the ground state was expected to be much 

Element 104. Similar considerations were applied to Rf when it was expected to have a ground state [41] and later a 7s 6d7p state according to 

MCDF calculations [68,69]. It was thought that if Rf has the configuration 7s 6d, then its heat of sublimation should be similar to that of Hf ( 6.33 eV). 

On the other hand, if the configuration is 7s 7pi/2, then its heat of sublimation should be similar to Pb ( 2.04 eV). The difference of 4 eV could easily be detected in experiments. The AHjub of Rf (6d7s 7p) was estimated as 540 - 694 kJ/mol. 

An experiment designed to check the p- or d-character of Rf has only given a lower limit of AHsub of 370 kJ/mol [186]. This value indicates that Rf is not as volatile as Sn or Pb, but rather non-volatile like analogous d elements. It was then decided to study the volatility of transactinide d-elements in the form of volatile halides of oxyhalides, because too high temperatures (much beyond 1000 °C) were needed to stabilize the 6d elements in an elemental state. 

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