Chemical isolation of dubnium (element 105) in fluoride media

Abstract

Element 105 / Dubnium / Fluoride / Ion exchange chromatographySummary. The isotope 262 Db was produced by irradiation of a 248 Cm target with 106-MeV 19 F ions at the 15 MV MP Tandem accelerator of Orsay (France). The reaction products were continuously and rapidly transported with a KCl aerosol helium jet system to the chemistry setup. They were dissolved in HF medium and the solution was passed through three successive ion exchange columns, allowing a continuous high level purification of Db from actinides on a first cation exchange column, the isolation of Db on an anion exchange one, and the retention of the long-lived decay products of 262 Db (3.24 h-254 Fm) on a second cation exchange column. Just after the end of irradiation, the decay products were desorbed from this column, purified and α-sources were prepared on carbon foil by electrospray. In 13 effective irradiation hours, 22 events corresponding to the α-decay of 254 Fm were recorded. Almost 70 atoms of 262 Db, produced in the reaction 248 Cm + 19 F were isolated in dilute HF medium. Like its homologues/analogues Nb, Ta and Pa, dubnium forms, with fluoride ions, negatively charged complexes which are strongly retained on anion exchanger.

Chemistry of Superheavy Elements

“…First experiments have been performed with Rf to study the fluoride complexation [158,159,161] and with Db. [163,164] Rf and Db, transported by the He(KCl) jet to the chemistry apparatus, were continuously dissolved, and this solution was passed through three consecutive ion-exchange columns. Primary produced divalent and trivalent actinides were "filtered" out on the first cation-exchange column.…”

“…[202,205] The fluoride complexation of Db in 0.2 m HF was recently confirmed in an experiment which used three consecutive ion-exchange columns-a cation exchange (filter) column, an anion exchange (chromatography) column, and another (filter) cation exchange column. [163] It was shown that Db forms an anionic fluoride complex which is strongly retained on the anion-exchange resin.…”

Chemie superschwerer Elemente

“…Das chemische Verhalten von Transactinoiden wird später aus dem Verhältnis der langlebigen Tochteraktivitäten in der einen oder anderen Fraktion bestimmt. Erste Experimente sind mit Rf zur Untersuchung der Fluorid‐Komplexbildung158, 159, 161 und auch schon mit Db durchgeführt worden 163. 164 Die mit einem He(KCl)‐Jet zu der Chemieapparatur transportierten Rf‐ und Db‐Atome wurden in kontinuierlich fließenden Elutionsmitteln gelöst, die durch drei aufeinander folgende Ionenaustauschersäulen gepumpt wurden.…”

“…Alle neueren experimentellen Studien, die jeweils im reinen F − ‐, Cl − ‐ und Br − ‐System durchgeführt wurden,204 stimmen ausgezeichnet mit den theoretischen Vorhersagen überein, die relativistische Effekte beinhalten 202. 205 Die Fluorid‐Komplexbildung von Db in 0.2 M HF wurde kürzlich in einem Experiment bestätigt, in dem drei aufeinander folgende Ionenaustauschersäulen eingesetzt wurden – eine Kationenaustauschersäule (Filter), eine Anionenaustauschersäule (Chromatographie) sowie eine weitere Kationenaustauschersäule (Filter) 163. Es wurde gezeigt, dass Db einen anionischen Fluorid‐Komplex bildet, der auf dem Anionenaustauscherharz stark zurückgehalten wird.…”

Adsorption of Db and its homologues Nb and Ta, and the pseudo-homologue Pa on anion-exchange resin in HF solution

“…Several attempts to clarify chemical properties of Db in aqueous solution have been made by extraction and ionexchange chromatography methods [7][8][9][10][11][12][13]. Comparative studies of Db with its lighter homologues Nb and Ta, and the pseudo-homologue Pa were carried out.…”