Speaker
Prof.
Jens Volker Kratz
(University of Mainz)
Description
Advanced methods that have been developed and applied to study the chemical properties of the transactinide elements in comparison with their lighter homologs are presented.These include thermochromatography, and isothermal chromatography in the gas phase as well as ion-exchange and reversed-phase liquid chromatography in the aqueous phase, liquid-liquid extraction, and electrodeposition. Latest applications of these methods to studies of the chemistry of the transactinides are shown.
From a systematic study of the anion-exchange behavior of Rf, it has been concluded that the properties of Rf in HCl and HNO3 solutions are similar to those of Zr and Hf [1-3]. However, in HF solutions, the fluoride complex formation of Rf is significantly different to that of its homologs [4-8]. In dilute HNO3/HF, the nitrate ion is the counter ion that removes the Rf hexafluoride di-anion more effectively from the binding sites of the anion-exchange resin than the Zr and Hf fluoride complexes. In strong HF solutions, it is the HF2- ion, that removes Rf much earlier from the anion-exchange resin than the much stronger fluoride complexes of Zr and Hf [6,7]. Chloride and fluoride complexation of Db has been studied in reversed-phase extraction chromatography with an aliphatic amine [9]. Chelating of Db with alpha-hydroxyisobutyrate was shown to be much stronger than for tetravalent and trivalent metal ions [10]. Sg has been eluted from a cation-exchange column as Sg oxyfluoride complex [11]. In 0.1 M HNO3, hydrolysis of Sg is weaker than that of Mo and W [12]. Successive deprotonation leads to a cationic species for Sg, while for Mo and W, neutral hydrolysed species are eluted from a cation-exchange column. In the gas phase, Sg was volatilized as SgO2Cl2 [13] and as SgO2(OH)2 [14]. Elements 107 and 108 were transported in the gas phase as BhO3Cl [15] and HsO4 [16]. In [17], the highly volatile HsO4 was deposited on a thin layer of NaOH in the presence of water vapor, thus forming a salt in analogy to the formation of an osamate (VIII). This shows that HsO4, like OsO4, is an acid anhydride. Most recently, first chemical studies were performed with elements 112 [18] and 114 [19]. Element 112 in its atomic state was shown to be very volatile, but unlike radon, reveals a metallic interaction with a Au surface [18]. Preliminary results on the volatility of element 114 in its atomic state indicate that it is a very volatile element with a weaker metallic interaction with a Au surface than 112 [19]. This surprising result needs to be confirmed.
[1] H. Haba et al.,(2002). [2] R. Günter et al.,(1998). [3] H. Haba et al., (2007). [4] E. Strub et al., (2000). [5] A. Kronenberg et al., (2004). [6] H. Haba et al., (2004). [7] Y. Nagame et al., A. Toyoshima et al., (2004). [9] W. Paulus et al., (1999). [10] M. Schädel et al., (1992). [11] M. Schädel et al., (1997). [12] M. Schädel et al., (1998). [13] A. Türler et al., (1998). [14] S. Hübener et al., (2001). [15] R. Eichler et al., (2000). [16] Ch. E. Düllmann et al., (2002). [17] A. von Zweidorf et al., (2004). [18] R. Eichler et al., 2007). [19] R. Eichler et al., (2009).
Primary author
Prof.
Jens Volker Kratz
(University of Mainz)
