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Journal Articles

Measurement of the Md$$^{3+}$$/Md$$^{2+}$$ reduction potential studied with flow electrolytic chromatography

Toyoshima, Atsushi; Li, Z.*; Asai, Masato; Sato, Nozomi; Sato, Tetsuya; Kikuchi, Takahiro; Kaneya, Yusuke; Kitatsuji, Yoshihiro; Tsukada, Kazuaki; Nagame, Yuichiro; et al.

Inorganic Chemistry, 52(21), p.12311 - 12313, 2013/11

https://doi.org/10.1021/ic401571h
 Times Cited Count：6 Percentile：23.49(Chemistry, Inorganic & Nuclear)

The reduction behavior of mendelevium (Md) was studied using a flow electrolytic chromatography apparatus. By applying appropriate potentials on the chromatography column, the more stable Md$$^{3+}$$ is reduced to Md$$^{2+}$$. The reduction potential of the Md$$^{3+}$$ + e$$^{-}$$ $$rightarrow$$ Md$$^{2+}$$ couple was determined to be -0.16$$pm$$0.05 V vs. a normal hydrogen electrode.

Journal Articles

Sulfate complexation of element 104, Rf, in H$$_{2}$$SO$$_{4}$$/HNO$$_{3}$$ mixed solution

Li, Z.*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Sato, Nozomi; Kikuchi, Takahiro; Nagame, Yuichiro; Sch$"a$del, M.; Pershina, V.*; et al.

Radiochimica Acta, 100(3), p.157 - 164, 2012/03

https://doi.org/10.1524/ract.2012.1898
 Times Cited Count：14 Percentile：68.93(Chemistry, Inorganic & Nuclear)

Journal Articles

Anionic fluoro complex of element 105, Db

Kasamatsu, Yoshitaka*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Li, Z.; Ishii, Yasuo; Tome, Hayato*; Sato, Tetsuya; Kikuchi, Takahiro; Nishinaka, Ichiro; et al.

Chemistry Letters, 38(11), p.1084 - 1085, 2009/10

https://doi.org/10.1246/cl.2009.1084
 Times Cited Count：16 Percentile：48.84(Chemistry, Multidisciplinary)

We report on the characteristic anion-exchange behavior of the superheavy element dubnium (Db) with atomic number Z = 105 in HF/HNO$$_{3}$$ solution at the fluoride ion concentration [F$$^{-}$$] = 0.003 M. The result clearly demonstrates that the fluoro complex formation of Db is significantly different from that of the group-5 homologue Ta in the 6th period of the periodic table while the behavior of Db is similar to that of the lighter homologue Nb in the 5th period.

Oral presentation

Anion-exchange experiments of nuclear reaction products transported by He/KCl and He/KF gas-jet systems

Kasamatsu, Yoshitaka; Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Ishii, Yasuo; Nishinaka, Ichiro; Sato, Tetsuya; Li, Z.; Kikuchi, Takahiro; Nagame, Yuichiro; et al.

no journal, , 

Radioactive nuclides of Nb and Ta were produced in the Zr/Hf(p,xn)Nb/Ta and Ge/Gd($$^{19}$$F,xn)Nb/Ta reactions at the JAEA tandem accelerator. The products were rapidly transported by He/KCl and He/KF gas-jet systems to the chemistry laboratory. It was found that the transport efficiency using the He/KF gas-jet system is comparable with that by the He/KCl gas-jet system which has been generally used. Subsequently, on-line anion-exchange experiments with the products were performed in HF/HNO$$_{3}$$ solutions. A small physical adsorption of Nb on the surfaces of the tools was observed when the KCl aerosols were used, while better reproducibility of the elution of Nb was obtained using the KF aerosols. We interpret that stable fluoro complexes of Nb are rapidly formed by using the KF aerosols and we can suggest that the He/KF gas-jet system should be used in the on-line anion-exchange experiment of the group 5 elements for the study of the fluoride complexation of the elements.

Oral presentation

Anion-exchange behavior of element-105 (Db) in HF/HNO$$_3$$ solutions using a newly developed on-line experimental system

Tsukada, Kazuaki; Kasamatsu, Yoshitaka; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Li, Z.; Kikuchi, Takahiro; Sato, Tetsuya; Nishinaka, Ichiro; Nagame, Yuichiro; et al.

no journal, , 

Anion-exchange chromatographic behavior of element 105, dubnium (Db), produced in the $$^{248}$$Cm($$^{19}$$F,5n)$$^{262}$$Db reaction is investigated together with the homologues Nb and Ta in HF/HNO$$_3$$ mixed media using a newly developed on-line experimental system. The result indicates that the adsorption sequence on the anion-exchange resin is Ta$$gg$$Nb$$geq$$Db, and the fluoride complex formation of Db is expected to be weaker than that of homologues.

Oral presentation

Anion-exchange behavior of Db in HF/HNO$$_{3}$$ mixed solution using a new on-line chemical apparatus

Tsukada, Kazuaki; Kasamatsu, Yoshitaka*; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Li, Z.; Kikuchi, Takahiro; Sato, Tetsuya; Nishinaka, Ichiro; Nagame, Yuichiro; et al.

no journal, , 

Anion-exchange chromatographic behavior of element 105, dubnium (Db), produced in the $$^{248}$$Cm($$^{19}$$F,5n) reaction is investigated together with the homologues Nb and Ta in HF/HNO$$_{3}$$ mixed media using a newly developed on-line experimental system. The result indicates that the adsorption sequence on the anion-exchange resin is Ta $$gg$$ Nb $$geq$$ Db, and the fluoride complex formation of Db is expected to be weaker than that of homologues.

Oral presentation

Cation-exchange behavior of Zr, Hf, and Th in H$$_{2}$$SO$$_{4}$$/HNO$$_{3}$$ mixed solutions; Towards to study on sulfate complexation of $$^{104}$$Rf

Li, Z.; Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Sato, Tetsuya; Kikuchi, Takahiro; Sato, Nozomi; Nagame, Yuichiro

no journal, , 

Oral presentation

Reduction of element 101, mendelevium, with flow electrolytic column chromatography

Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Sato, Tetsuya; Li, Z.; Sato, Nozomi; Kikuchi, Takahiro; Kitatsuji, Yoshihiro; Nagame, Yuichiro; Oe, Kazuhiro*; et al.

no journal, , 

Reduction of element 101, mendelevium (Md), was studied with flow electrolytic chromatography. Mendelevium-255 with a half-life of 27 min was produced in the $$^{248}$$Cm($$^{11}$$B, 4n) reaction at the JAEA tandem accelerator. Reaction products transported by a KCl/He gas-jet method to the chemistry laboratory were collected on a chemistry apparatus. After removing KCl with HDEHP chromatography, elution behavior of Md in 0.1 M HCl was investigated with a flow electrolytic column apparatus at the applied potentials between 0 $$sim$$ -0.9 V vs. a Ag/AgCl reference electrode. Elution behavior of Md was the same as that of $$^{250}$$Bk$$^{3+}$$ at 0 V, showing that the stable Md$$^{3+}$$ was not reduced to the divalent state. At -0.9 V, elution of Md was quite similar to that of Sr$$^{2+}$$, demonstrating that Md$$^{3+}$$ was successfully reduced to Md$$^{2+}$$.

Oral presentation

Electrochemistry of the heaviest elements at JAEA

Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Kitatsuji, Yoshihiro; Ishii, Yasuo; Sato, Tetsuya; Li, Z.; Sato, Nozomi; Kikuchi, Takahiro; Nishinaka, Ichiro; et al.

no journal, , 

Oxidation of element 102, nobelium (No), using a developed electrolytic chromatography apparatus on an atom-at-a-time scale will be presented. It was found that the most stable ion, No$$^{2+}$$, is oxidized to No$$^{3+}$$ in $$alpha$$-hydroxyisobutyric acid ($$alpha$$-HIB) solution using the apparatus and that the oxidized No complex with $$alpha$$-HIB holds the trivalent state in the column above an applied potential of 1.0 V. Electrochemical reduction of element 101, mendevelium (Md) in HCl will be also presented.

Oral presentation

On-line isothermal gas chromatographic behavior of group 5 elements Nb and Ta as homologues of Db

Sato, Tetsuya; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Li, Z.; Sato, Nozomi; Kikuchi, Takahiro; Nagame, Yuichiro

no journal, , 

To investigate chemical properties of the transactinide element dubnium (Db, Z=105), we have developed an on-line isothermal gas chromatographic apparatus. The on-line experiments with the group-5 elements using the short lived $$^{88}$$Nb and $${170}$$Ta as the homologues of Db were conducted. We measured the relative chemical yields of volatile compounds of $${88}$$Nb and $${170}$$Ta as a function of the isothermal temperature in chlorinating condition with mixture of air and the SOCl$$_2$$ vapor. It was found that the volatility of compounds of Ta is lower than that of Nb.

Oral presentation

Development of an on-line isothermal gas chromatographic apparatus for Db and Sg

Sato, Tetsuya; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Li, Z.; Sato, Nozomi; Kikuchi, Takahiro; Haba, Hiromitsu*; Goto, Shinichi*; et al.

no journal, , 

To investigate chemical properties of the transactinide elements dubnium (Db, Z = 105) and seaborgium (Sg, Z = 106), we have developed an on-line isothermal gas chromatographic apparatus. The on-line experiments with the group-5 and -6 elements using the short lived 88Nb and 170Ta as the homologues of Db and 173W as the one of Sg were conducted. We measured the relative chemical yields of volatile compounds of 88Nb, 170Ta and 173W as a function of the isothermal temperature. The behavior of W and Nb was the same as that obtained in previous work by M. Gartner et al., and A. Turler et al., respectively. It was found that the volatility of compounds of Ta is lower than that of Nb.

Oral presentation

Chemical investigation of Rf and Db at JAEA

Nagame, Yuichiro; Asai, Masato; Ishii, Yasuo; Kikuchi, Takahiro; Li, Z.; Sato, Tetsuya; Toyoshima, Atsushi; Tsukada, Kazuaki; Kasamatsu, Yoshitaka*; Haba, Hiromitsu*; et al.

no journal, , 

no abstracts in English

Oral presentation

$$alpha$$-HiB complexation of Zr and Hf as homologues of Rf

Kikuchi, Takahiro; Toyoshima, Atsushi; Li, Z.; Tsukada, Kazuaki; Asai, Masato; Sato, Tetsuya; Sato, Nozomi; Nagame, Yuichiro; Kasamatsu, Yoshitaka*; Fan, F.*

no journal, , 

The ion-exchange behavior of Zr and Hf in $$alpha$$-HiB / HNO$$_{3}$$ mixed solutions has been studied by a batch method using the carrier-free radiotracers $$^{88}$$Zr and $$^{175}$$Hf. It is found that the $$alpha$$-HiB complex formation of Zr and Hf reaches equilibrium in 180 min and that the ion-exchange behavior of these elements are basically similar to each other. The distribution coefficients of Zr and Hf on the cation-exchange resin at [H$$^{+}$$]$$_{eq}$$ = 0.1 M decrease with an increase of [$$alpha$$-HiB$$^{-}$$]$$_{eq}$$, reflecting successive formation of $$alpha$$-HiB complexes.

Oral presentation

Anion-exchange behavior of element-105, Db in HF/HNO$$_{3}$$ mixed solution

Kasamatsu, Yoshitaka*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Li, Z.; Ishii, Yasuo; Sato, Tetsuya; Nishinaka, Ichiro; Kikuchi, Takahiro; Haba, Hiromitsu*; et al.

no journal, , 

Dubnium-262 was produced in the $$^{248}$$Cm($$^{19}$$F, 5n) reaction at the JAEA tandem accelerator. Reaction products were rapidly transported by a He/KF gas-jet system to the chemistry laboratory. Anion-exchange behavior of Db in HF/HNO$$_{3}$$ solution was then investigated using the newly developed on-line ion-exchange and $$alpha$$-particle detection apparatus. Distribution coefficients of Db were clearly smaller than those of Ta, the closest homologue in the periodic table, and were close to those of lighter homologue Nb and also the pseudo homologue Pa. Fluoride complex formation of Db will be discussed.

Oral presentation

Reduction of mendelevium (Md) with electrochemistry

Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Sato, Tetsuya; Li, Z.; Sato, Nozomi; Kikuchi, Takahiro; Kitatsuji, Yoshihiro; Nagame, Yuichiro; Oe, Kazuhiro*; et al.

no journal, , 

Reduction of mendelevium (Md) was studied by an electrochemical method on a single atom scale. Mendelevium-255 produced in the $$^{248}$$Cm($$^{11}$$B,4n) reaction at the JAEA tandem accelerator was transported to a chemistry laboratory by a gas-jet method. The Md isotope was then dissolved with 0.1 M HCl and fed into a working electrode modified with cation-exchange resin of a flow electrolytic column apparatus. The elution behavior on the electrode was examined as a function of the applied potential. It was found that trivalent ion of Md is reduced to the divalent state at the potentials below -0.4 V vs. an Ag/AgCl reference electrode.

Oral presentation

Electrochemistry of the heaveist elements

Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Kitatsuji, Yoshihiro; Ishii, Yasuo; Sato, Tetsuya; Li, Z.; Sato, Nozomi; Kikuchi, Takahiro; Nishinaka, Ichiro; et al.

no journal, , 

Electrochemical studies of nobelium (No) and mendelevium (Md) using an electrolytic column chromatography at JAEA will be presented. The isotopes $$^{255}$$No and $$^{255}$$Md were produced in the $$^{248}$$Cm($$^{12}$$C, 5n) and $$^{248}$$Cm($$^{11}$$B, 4n) reactions, respectively, at the JAEA tandem accelerator. In the experiment of No, the oxidation of No$$^{2+}$$ to No$$^{3+}$$ in 0.1 M $$alpha$$-hydroxyisobutyric acid ($$alpha$$-HIB) was studied with comparing with the elution of Sr$$^{2+}$$ and Yb$$^{3+}$$. At the applied potential of 0.2 V, No was not eluted with $$alpha$$-HIB. This adsorption of No was the same as that of Sr$$^{2+}$$, indicating that No was bound in its stable divalent state. On the other hand, the elution of No in $$alpha$$-HIB was observed at 1.2 V at the position of Yb$$^{3+}$$, which demonstrated that No$$^{2+}$$ was successfully oxidized to No$$^{3+}$$. Reduction of Md$$^{3+}$$ to Md$$^{2+}$$ was also successfully carried out with the apparatus in 0.1 M HCl.

Oral presentation

Anion-exchange behavior of Db in HF/HNO$$_{3}$$ mixed solution using an on-line chemical apparatus

Tsukada, Kazuaki; Kasamatsu, Yoshitaka*; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Li, Z.; Kikuchi, Takahiro; Sato, Tetsuya; Nagame, Yuichiro; Sch$"a$del, M.; et al.

no journal, , 

We have investigated the chemical behavior of Db together with its group-5 homologues by anion-exchange chromatography in HF/HNO$$_{3}$$ mixed solution using a rapid online chemical apparatus (AIDA-II). The nuclides $$^{262}$$Db, $$^{88}$$Nb and $$^{169,170}$$Ta were produced in the $$^{248}$$Cm($$^{19}$$F, ${it 5}$n), $$^{nat}$$Ge($$^{19}$$F, ${it x}$n) and $$^{nat}$$Gd($$^{19}$$F, ${it x}$n) reactions, respectively, at the JAEA tandem accelerator. On-line anion-exchange separations of Db, Nb and Ta were performed using the AIDA-II. Thousand times of anion-exchange separations were conducted using AIDA-II. $$alpha$$ events were registered, and the $${it K_d}$$ values for Db was evaluated. From these results, the adsorption sequence Pa $$<$$ Db $$<$$ Nb $$ll$$ Ta was determined. The present result shows a notable difference in the adsorption behavior between Db and its homologue Ta. In the conference, the present status and the perspective of the aqueous chemistry of Db at JAEA will be also presented.

Oral presentation

Sulfate complexation of element 104, Rf, in H$$_{2}$$SO$$_{4}$$/HNO$$_{3}$$ mixed solution ([H$$^{+}$$] = 1.0 M)

Li, Z.; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Sato, Nozomi; Kikuchi, Takahiro; Sch$"a$del, M.*; Nagame, Yuichiro; Liang, X. H.*; et al.

no journal, , 

Cation-exchange behavior of $$^{261}$$Rf (T$$_{1/2}$$ = 78 s) produced in the $$^{248}$$Cm($$^{18}$$O, 5n) reaction was studied on a "one-atom-at-a-time" scale in H$$_{2}$$SO$$_{4}$$ (0.15-0.69 M)/HNO$$_{3}$$ mixed solutions ([H$$^{+}$$] = 1.0 M) using an automated ion-exchange separation apparatus coupled with the detection system for alpha-spectroscopy. It was found that adsorption probability (%ads) of $$^{261}$$Rf on cation-exchange resin decreases with increasing [HSO$$_{4}$$$$^{-}$$], showing a successive formation of its sulfate complexes. Rf exhibited much weaker formation of the complexes than the lighter homologues Zr and Hf, which is qualitatively in good agreement with theoretical calculations including relativistic effects.

Oral presentation

$$alpha$$-HiB complexation and ion-exchange behavior of the group-4 elements as homologues of Rf

Kikuchi, Takahiro; Toyoshima, Atsushi; Li, Z.; Tsukada, Kazuaki; Asai, Masato; Sato, Tetsuya; Sato, Nozomi; Nagame, Yuichiro; Kasamatsu, Yoshitaka*; Fan, F.*

no journal, , 

We studied complexation of the group-4 elements Zr and Hf as well as the pseudo group-4 element Th with $$alpha$$-hydroxyisobutyric acid ($$alpha$$-HiB) as homologues of Element 104, rutherfordium (Rf). The isotopes of $$^{88}$$Zr and $$^{175}$$Hf were produced at the JAEA tandem accelerator while $$^{234}$$Th was separated from $$^{238}$$U. These radiotracers stocked in $$alpha$$-HiB/HNO$$_{3}$$ were mixed with cation-exchange resin. After shaking the sample for a certain time, an aliquot of the aqueous phase was precisely taken, which were subjected to $$gamma$$-spectrometry. The complex formation of Zr and Hf reached to chemical equlibria at 180 min. Distribution coefficients of Zr and Hf were decreased with an increase of the concentration of $$alpha$$-HiB, indicating the consecutive complexation of these ions with $$alpha$$-HiB. On the other hand, Th was adsorbed on the cation-exchange resin under the given conditions, showing clearly different behavior of Th from that of Zr and Hf.

Oral presentation

Anion-exchange behavior of the group-6 elements in HF/HNO$$_{3}$$ mixed solutions; Towards the study of ion-exchange behavior of $$^{106}$$Sg

Liang, X.; Li, Z.; Tsukada, Kazuaki; Toyoshima, Atsushi; Asai, Masato; Sato, Tetsuya; Sato, Nozomi; Kikuchi, Takahiro; Kaneya, Yusuke; Nagame, Yuichiro

no journal, , 

Anion-exchange behavior of the group-6 elements, W and Mo, in HF and HNO$$_{3}$$ mixed solutions has been studied by a batch method using the carrier-free radiotracers $$^{rm 181}$$W and $$^{rm 93m}$$Mo. The long-lived isotope $$^{181}$$W and the short-lived isotope $$^{rm 93m}$$Mo were produced in the $$^{181}$$Ta(p,n) and the $$^{93}$$Nb(p,n) reaction at the JAEA tandem accelerator, respectively. The solutions containing $$^{rm 181}$$W or $$^{rm 93m}$$Mo were mixed with anion exchange resin. Radioactivities of the solution were assayed for $$gamma$$-ray spectrometry, and then distribution coefficients (K$$_{d}$$s) of these elements were determined. It was found that the K$$_{d}$$ values of W depend strongly on the concentration of HF, while those of Mo are almost constant as a function of [HF] under the given conditions.

33 (Records 1-20 displayed on this page)