Chemical Properties of Element 105 in Aqueous Solution: Back Extraction from Triisooctyl Amine into 0.5 M HCl

Abstract

Previous studies of the halide complex formation of element 105 and its anion exchange with triisooctyl amine (TIOA) were continued. The experiments were performed on a one-minute time scale with the computer-controlled liquid chromatography system ARCA II on a mixture of 34-s 262 Ha and 27-s 263 Ha produced in the 249 Bk( 18 0,5n) and 249 Bk( 18 0,4n) reactions at a beam energy of 99 MeV. The Ha isotopes were detected by measuring the spontaneous fission and α-activities associated with their decay, and the α-decays of their daughters, 4-s 258 Lr, and 6-s 259 Lr. Time-correlated pairs of parent and daughter α-particles were also registered. 262,263 Ha was absorbed on the TIOA columns from either 12 M HCl/0.01 M HF or 10 M HCl, and was subsequently eluted in 0.5 M HCl/0.01 M HF like its homolog niobium, and the pseudohomolog protactinium, and unlike the closest homolog, tantalum, which remains in the amine phase under these conditions. The effluent was divided into an early Pa fraction and a subsequent Nb fraction. By varying the cut between the Pa fraction and the Nb fraction in rough steps, it was shown that the elution of element 105 occurs closer to the Pa elution position, i.e., earlier than the elution of Nb. These results confirm the non-tantalum like behavior of element 105 in 0.5 M HCl/0.01 M HF, and corroborate previously suggested structural differences between the halide complexes of element 105, niobium, and protactinium, on the one hand, and those of tantalum on the other hand.

Critical evaluation of the chemical properties of the transactinide elements (IUPAC Technical Report)

“…It is then necessary, in order to get a statistically significant result, to repeat the same experiment several hundred or even several thousand times with a cycle time of typically 1 min. Recent discontinuous studies were either performed manually [71][72][73][74][75][76] or with the automated rapid chemistry apparatus, ARCA II [40,41,43,[77][78][79][80][81][82][83].…”

Chemistry of superheavy elements

“…At 4 M HCl/0.02 M HF, it came as a big surprise, that Db followed Nb and Pa and not Ta. At 6 M HNO 3 /0.0015 M HF, Db showed an intermediate behavior between Pa and Nb indicating that the halide complexing strength of Db is in between that for Nb and Pa. At 0.5 M HCl/0.01 M HF, Db even showed more Palike properties [195]. These stunning results provided strong motivation to investigate Db further.…”

Discovery of the elements with atomic numbers Z = 113, 115 and 117 (IUPAC Technical Report)

“…These investigations looked at the extraction of Db in strong acid organic ligand partitions, the latter being methyl isobutyl ketone [29], diisobutylcarbinol [30], triisooctylamine [31], Aliquat 336 [32], and in cation exchange using α-hydroxyisobutyric acid [33]. As in all of the published separation schemes, radiotracers are added to follow congeners niobium and tantalum and lanthanide radiotracers serve as proxies for actinide behavior.…”