Transactinoid elements

Fig. 1.1 Volatile compounds and elemental forms characteristic of the lighter homologs of transactinoid elements.

Figure 1.1 shows some volatile compounds formed by the common elements of groups 4 to 11, as well as the relatively volatile metals of groups 12 to 14. The compounds of transactinoid elements with supposedly similar stoichiometry have been studied in works reported by now. A few studies have also been done with bromides and oxybromides. 

Production of Transactinoid Elements, Synthesis and Transportation of Compounds... 

One of the basic requirements is to synthesize the desirable compounds and to rapidly transport them to the equipment for chemical experiments. The time spent to accomplish such processes and its probability distribution can be properly determined only when a radioisotope of the element under study can be produced in a quantity that can be easily and accurately measured. It has never been the case for the transactinoid elements. Rough estimation of the chlorination time of Zr and Mo was done in the model experiments described in the above Section (see also Fig. 1.2). The ampoule was filled with pure inert gas, then closed and bombarded for some time with neutrons at ambient temperature. Thus, the thermalized fission products were accumulated on the walls. Then the ampoule was heated and flushed for a short time with the gas containing a reagent. Most of the activity got transferred into the nap in 30 seconds or so it involved a mean gas hold-up time of 15 seconds, so that the actual upper limit of the chlorination time could be set as 15 seconds. 

Unfortunately, in the continuous on-line experiments with transactinoid elements, the application of the above Second Law and related procedures has not been possible because of the very poor statistics of detected decays. Measurements of this type have been done only with long-lived lighter homologs of the transactinoids in batch tests. Packed columns and low flow rates of the carrier gas were employed to achieve narrow peaks. Major contribution came from Bachmann and co-workers. In Refs. [6,9-11] they measured the adsorption enthalpies and entropies on solid... 

Typically the experiment with a transactinoid element lasts days or even weeks, and results in a single experimental value of the adsorption constant. The only possibility to obtain an estimate of the adsorption enthalpy based on such a result is to calculate the entropy change from the first principles [4] and substitute it into Eq. 5.7. The values of Aa( sS are calculated from the formulae of statistical mechanics for the particular model of the adsorbed state. The evaluation starts with the partition function of single molecule qm and with the molar partition function Z to calculate the absolute molar entropy from the general equation ... 

Chapter 1 presents some details of the experimental developments which were important steps forward. It also briefly describes a few typical concrete studies of the transactinoid elements. The emphasis is on novel approaches, techniques and classes of the utilized compounds, as well as on posing and solving problems. Consistently, the presentation tends to comply, if possible, with both the historical and logical sequences of the events. Closing sections of the chapter consider various classes of inorganic compounds, other than the widespread chlorides, as to their prospects for future studies. 

Transuranium, transplutonium, (and so forth) elements are essentially all elements with atomic numbers higher than that specified by the name no upper limit is implied. In the meantime, for what are essentially translawrencium elements, the radiochemical community uses the improper term transactinoid elements (TAEs). Nevertheless, we will stick to the latter because it emphasizes that, after a long row of elements of the actinoid character, one again deals with -elements, each of which must have distinct individual chemistry. 

Identify the starting isotopes A-E in each of the following syntheses of transactinoid elements ... 

Oganessian, Yu.Ts. Synthesis reactions and radioactive properties of transactinoid elements. J. Alloys Compd. 213 14, 50-60 (1994)... 

Zvara, I. Gas phase chemistiy studies of transactinoid elements and the relativistic effects. Czech J. Phys. 49, 563-571 (1999)... 

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