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Co-precipitation behaviour of single atoms of rutherfordium in basic solutions


All superheavy elements (SHEs), with atomic numbers (Z) ≥104, have been artificially synthesized one atom at a time and their chemical properties are largely unknown. Because these heavy nuclei have short lifetimes as well as extremely low production rates, chemical experiments need to be carried out on single atoms and have mostly been limited to adsorption and extraction. We have now investigated the precipitation properties of the SHE Rf (Z = 104). A co-precipitation method with samarium hydroxide had previously established that the co-precipitation behaviour of a range of elements reflected these elements’ tendency to form hydroxide precipitates and/or ammine complex ions. Here we investigated co-precipitation of Rf in basic solutions containing NH3 or NaOH. Comparisons between the behaviour of Rf with that of Zr and Hf (lighter homologues of Rf) and actinide Th (a pseudo-homologue of Rf) showed that Rf does not coordinate strongly with NH3, but forms a hydroxide (co)precipitate that is expected to be Rf(OH)4.

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Fig. 1: Schematic of the online co-precipitation experiment on 261Rf.
Fig. 2: α spectrum of co-precipitated sample prepared using 6 M NaOH.
Fig. 3: The co-precipitation yields of Rf together with those of Zr, Hf and Th.

Data availability

The data that support the findings of this study are included with the article and Supplementary Information. Source data for Figs. 2 and 3 are provided with the paper. Source data are provided with this paper.


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This work was performed at the RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo. The authors are grateful to the staff members of RIKEN Nishina Center for their excellent beam operation. This work was supported by JSPS KAKENHI grant numbers 24655050 and 16K05815.

Author information




Y. Kasamatsu, H.H., H.K., T. Yokokita and A.S. wrote the main part of the manuscript. K. Toyomura and Y. Kasamatsu mainly conducted the experiments and were responsible for data analysis. H.H., T. Yokokita, Y.S., Y. Komori, J.K., M.H., M.M., A.K., Y.Y. and H.K. contributed to the online experiments and E. W., T. Yoshimura and K.M. contributed to the discussion of results. H.K., K. Takamiya, Y. Kasamatsu, T.O. and T.M. developed the co-precipitation method.

Corresponding author

Correspondence to Yoshitaka Kasamatsu.

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Supplementary information

Supplementary Information

Supplementary discussions, Fig. 1 and Tables 1 and 2.

Source data

Source Data Fig. 1

Statistical source data for Fig. 2.

Source Data Fig. 2

Statistical source data for Fig. 3.

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Kasamatsu, Y., Toyomura, K., Haba, H. et al. Co-precipitation behaviour of single atoms of rutherfordium in basic solutions. Nat. Chem. 13, 226–230 (2021).

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