Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Isolation of a californium(II) crown–ether complex

Nature Chemistry volume 15, pages 722–728 (2023)Cite this article

Subjects

Abstract

The actinides, from californium to nobelium (Z = 98–102), are known to have an accessible +2 oxidation state. Understanding the origin of this chemical behaviour requires characterizing CfII materials, but investigations are hampered by the fact that they have remained difficult to isolate. This partly arises from the intrinsic challenges of manipulating this unstable element, as well as a lack of suitable reductants that do not reduce CfIII to Cf°. Here we show that a CfII crown–ether complex, Cf(18-crown-6)I2, can be prepared using an Al/Hg amalgam as a reductant. Spectroscopic evidence shows that CfIII can be quantitatively reduced to CfII, and rapid radiolytic re-oxidation in solution yields co-crystallized mixtures of CfII and CfIII complexes without the Al/Hg amalgam. Quantum-chemical calculations show that the Cf‒ligand interactions are highly ionic and that 5f/6d mixing is absent, resulting in weak 5f→5f transitions and an absorption spectrum dominated by 5f→6d transitions.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Reaction and isolation of Cf(18-crown-6)I2.
Fig. 2: Crystal structures of [CfII(18-crown-6)(H2O)2(CH3CN)][CfIII(18-crown-6)(H2O)(CH3CN)I]2+ and CfII(18-crown-6)I2.
Fig. 3: NLMOs.
Fig. 4: Solid-state and solution-phase UV–vis–NIR spectroscopy.
Fig. 5: LFDFT absorption spectroscopy of [CfII(18-crown-6)I2 and acetonitrile solutions containing Cf2+ or Cf3+ and 18-crown-6.

Similar content being viewed by others

Data availability

All of the relevant data that support the findings of this research are available within the Article and its Supplementary Information and via CCDC 2180138 (Dy(18-crown-6)I2) (https://www.ccdc.cam.ac.uk/structures/Search?access=referee&ccdc=2180138&Author=Todd+Poe), 2180139 ([Am(cis-syn-cis-dicyclohexano-18-crown-6)(H2O)(CH3CN)I]I2·CH3CN) (https://www.ccdc.cam.ac.uk/structures/Search?access=referee&ccdc=2180139&Author=Todd+Poe), 2180140 (Cf(18-crown-6)I2) (https://www.ccdc.cam.ac.uk/structures/Search?access=referee&ccdc=2180140&Author=Todd+Poe) and 2180141 ([CfII(18-crown-6)(H2O)2(CH3CN)][CfIII(18-crown-6)(H2O)(CH3CN)I]I2) (https://www.ccdc.cam.ac.uk/structures/Search?access=referee&ccdc=2180141&Author=Todd+Poe). Source data are provided with this paper.

References

  1. Clark, D. L. The chemical complexities of plutonium. Los Alamos Sci 26, 364–381 (2000).

    CAS  Google Scholar 

  2. Morss, L. R., Edelstein, N. M. & Fuger, J. The Chemistry of the Actinide and Transactinide Elements (Springer, 2010).

  3. Haire, R. G. in The Chemistry of the Actinide and Transactinide Elements (eds Morss, L. R., Edelstein, N. M. & Fuger, J.) 1499–1576 (Springer, 2010).

  4. Maly, J., Sikkeland, T., Silva, R. & Ghiorso, A. Nobelium: tracer chemistry of the divalent and trivalent ions. Science 160, 1114–1115 (1968).

    Article  CAS  PubMed  Google Scholar 

  5. Silva, R. J. in The Chemistry of the Actinide and Transactinide Elements (eds Morss, L. R., Edelstein, N. M. & Fuger, J.) 1621–1652 (Springer, 2010).

  6. Mikheev, Ν. Β, Auerman, L. Ν, Rumer, I. A., Kamenskaya, A. N. & Kazakevich, Μ. Ζ The anomalous stabilisation of the oxidation state 2+ of lanthanides and actinides. Russ. Chem. Rev. 61, 990–998 (1992).

    Article  Google Scholar 

  7. Langeslay, R. R., Fieser, M. E., Ziller, J. W., Furche, F. & Evans, W. J. Synthesis, structure and reactivity of crystalline molecular complexes of the {[C5H3(SiMe3)2]3Th}1− anion containing thorium in the formal +2 oxidation state. Chem. Sci. 6, 517–521 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  8. Woen, D. H. & Evans, W. J. Expanding the +2 oxidation state of the rare-earth metals, uranium and thorium in molecular complexes. Handb. Phys. Chem. Rare Earths 50, 337–394 (2016).

    Article  CAS  Google Scholar 

  9. Su, J. et al. Identification of the formal +2 oxidation state of neptunium: synthesis and structural characterization of {NpII[C5H3(SiMe3)2]3}1−. J. Am. Chem. Soc. 140, 7425–7428 (2018).

    Article  CAS  PubMed  Google Scholar 

  10. Windorff, C. J. et al. Identification of the formal +2 oxidation state of plutonium: synthesis and characterization of {PuII[C5H3(SiMe3)2]3}−. J. Am. Chem. Soc. 139, 3970–3973 (2017).

    Article  CAS  PubMed  Google Scholar 

  11. Dutkiewicz, M. S., Apostolidis, C., Walter, O. & Arnold, P. L. Reduction chemistry of neptunium cyclopentadienide complexes: from structure to understanding. Chem. Sci. 8, 2553–2561 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  12. Straub, M. D. et al. A uranium(II) arene complex that acts as a uranium(I) synthon. J. Am. Chem. Soc. 143, 19748–19760 (2021).

    Article  CAS  PubMed  Google Scholar 

  13. Lapierre, H. S., Kameo, H., Halter, D. P., Heinemann, F. W. & Meyer, K. Coordination and redox isomerization in the reduction of a uranium(III) monoarene complex. Angew. Chem. Int. Ed. 53, 7154–7157 (2014).

    Article  CAS  Google Scholar 

  14. Murillo, J. et al. Actinide arene-metalates: ion pairing effects on the electronic structure of unsupported uranium-arenide sandwich complexes. Chem. Sci. 12, 13360–13372 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Dau, P. D., Shuh, D. K., Sturzbecher-Hoehne, M., Abergel, R. J. & Gibson, J. K. Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(II). Dalton Trans. 45, 12338–12345 (2016).

    Article  CAS  PubMed  Google Scholar 

  16. Schöttle, C. et al. Nanosized gadolinium and uranium—two representatives of high-reactivity lanthanide and actinide metal nanoparticles. ACS Omega 2, 9144–9149 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  17. Marsh, M. L. et al. Electrochemical studies of selected lanthanide and californium cryptates. Inorg. Chem. 58, 9602–9612 (2019).

    Article  CAS  PubMed  Google Scholar 

  18. David, F., Samhoun, K., Guillaumont, R. & Edelstein, N. Thermodynamic properties of 5f elements. J. Inorg. Nucl. Chem. 40, 69–74 (1978).

    Article  CAS  Google Scholar 

  19. Bard, A. J. Standard Potentials in Aqueous Solution (International Union of Pure and Applied Chemistry, 1985).

  20. Silver, M. A. et al. Electronic structure and properties of Berkelium iodates. J. Am. Chem. Soc. 139, 13361–13375 (2017).

    Article  CAS  PubMed  Google Scholar 

  21. Wild, J. F. et al. Studies of californium(II) and (III) iodides. J. Inorg. Nucl. Chem. 40, 811–817 (1978).

    Article  CAS  Google Scholar 

  22. White, F. D. et al. Molecular and electronic structure, and hydrolytic reactivity of a samarium(II) crown ether complex. Inorg. Chem. 58, 3457–3465 (2019).

    Article  CAS  PubMed  Google Scholar 

  23. Poe, T. N., Molinari, S., Justiniano, S., McLeod, G. M. & Albrecht-Schönzart, T. E. Structural and spectroscopic analysis of Ln(II) 18-crown-6 and benzo-18-crown-6 complexes (Ln = Sm, Eu, Yb). Cryst. Growth Des. 22, 842–852 (2022).

    Article  CAS  Google Scholar 

  24. Brown, D., Fletcher, S. & Holah, D. G. The preparation and crystallographic properties of certain lanthanide and actinide tribromides and tribromide hexahydrates. J. Chem. Soc. A 67, 1889–1894 (1968).

    Article  Google Scholar 

  25. Xémard, M. et al. Divalent thulium crown ether complexes with field-induced slow magnetic relaxation. Inorg. Chem. 58, 2872–2880 (2019).

    Article  PubMed  Google Scholar 

  26. Merzlyakova, E. et al. 18-Crown-6 coordinated metal halides with bright luminescence and nonlinear optical effects. J. Am. Chem. Soc. 143, 798–804 (2021).

    Article  CAS  PubMed  Google Scholar 

  27. Rogers, R. D., Rollins, A. N., Etzenhouser, R. D., Voss, E. J. & Bauer, C. B. Structural investigation into the steric control of polyether complexation in the lanthanide series: macrocyclic 18-crown-6 versus acyclic pentaethylene glycol. Inorg. Chem. 32, 3451–3462 (1993).

    Article  CAS  Google Scholar 

  28. Rogers, R. D. et al. Direct comparison of the preparation and structural features of crown ether and polyethylene glycol complexes of NdCl3·6H2O. Inorg. Chem. 30, 4946–4954 (1991).

    Article  CAS  Google Scholar 

  29. Rogers, R. D., Kurihara, L. K. & Voss, E. J. f-Element/crown ether complexes. 5.1 Structural changes in complexes of lanthanide chloride hydrates with 18-crown-6 accompanying decreases in Ln3+ ionic radii: synthesis and structures of [M(OH2)7 (OHMe)][MCl(OH2)2(18-crown-6)]2Cl7·2H2O (M = Y, Dy). Inorg. Chem. 26, 2360–2365 (1987).

    Article  CAS  Google Scholar 

  30. Rogers, R. D. & Kurihara, L. K. f-Element/crown ether complexes. 4. Synthesis and crystal and molecular structures of [MCl(OH2)2(18-crown-6)]Cl2·2H2O (M = Sm, Gd, Tb). Inorg. Chem. 26, 1498–1502 (1987).

    Article  CAS  Google Scholar 

  31. Polinski, M. J. et al. Differentiating between trivalent lanthanides and actinides. J. Am. Chem. Soc. 134, 10682–10692 (2012).

    Article  CAS  PubMed  Google Scholar 

  32. Sperling, J. M. et al. Pressure-induced spectroscopic changes in a californium 1D material are twice as large as found in the holmium analog. Inorg. Chem. 59, 10794–10801 (2020).

    Article  CAS  PubMed  Google Scholar 

  33. Apostolidis, C. et al. [An(H2O)9](CF3SO3)3 (An = U–Cm, Cf): Exploring their stability, structural chemistry and magnetic behavior by experiment and theory. Angew. Chem. Int. Ed. 49, 6343–6347 (2010).

    Article  CAS  Google Scholar 

  34. Brenner, N. et al. Trivalent f-element squarates, squarate-oxalates, and cationic materials, and the determination of the nine-coordinate ionic radius of Cf(III). Inorg. Chem. 59, 9384–9395 (2020).

    Article  CAS  PubMed  Google Scholar 

  35. Wang, S., Alekseev, E. V., Depmeier, W. & Albrecht-Schmitt, T. E. Surprising coordination for plutonium in the first plutonium(III) borate. Inorg. Chem. 50, 2079–2081 (2011).

    Article  CAS  PubMed  Google Scholar 

  36. Mironov, Y. V., Cody, J. A., Albrecht-Schmitt, T. E. & Ibers, J. A. Cocrystallized mixtures and multiple geometries: syntheses, structures and NMR spectroscopy of the Re6 clusters [NMe4]4[Re6(Te(8 − n)Se(n))(CN)6] (n = 0–8). J. Am. Chem. Soc. 119, 493–498 (1997).

    Article  CAS  Google Scholar 

  37. Peterson, J. R., Fellows, R. L., Young, J. P. & Haire, R. G. Stabilization of californium(II) in the solid-state – californium dichloride, 249CfCl2. Radiochem. Radioanal. Lett. 31, 277–282 (1977).

    CAS  Google Scholar 

  38. Peterson, J. R. & Baybarz, R. D. The stabilization of divalent californium in the solid state: californium dibromide. Inorg. Nucl. Chem. Lett. 8, 423–431 (1972).

    Article  CAS  Google Scholar 

  39. Young, J. P., Vander Sluis, K. L., Werner, G. K., Peterson, J. R. & Noé, M. High temperature spectroscopic and X-ray diffraction studies of californium tribromide: proof of thermal reduction to californium(II). J. Inorg. Nucl. Chem. 37, 2497–2501 (1975).

    Article  CAS  Google Scholar 

  40. Izatt, R. M., Haymore, B. L., Bradshaw, J. S. & Christensen, J. J. Facile separation of the cis isomers of dicyclohexyl-18-crown-6. Inorg. Chem. 14, 3132–3133 (2002).

    Article  Google Scholar 

  41. Sheldrick, G. M. SHELXT—integrated space-group and crystal-structure determination. Acta Crystallogr. A Found. Crystallogr. 71, 3–8 (2015).

    Article  Google Scholar 

  42. Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. OLEX2: a complete structure solution, refinement and analysis program. J. Appl. Crystallogr. 42, 339–341 (2009).

    Article  CAS  Google Scholar 

  43. Poe, T. N. et al. Influence of outer-sphere anions on the photoluminescence from samarium(II) crown complexes. Inorg. Chem. 60, 15196–15207 (2021).

    Article  CAS  PubMed  Google Scholar 

  44. te Velde, G. et al. Chemistry with ADF. J. Comput. Chem. 22, 931–967 (2001).

    Article  Google Scholar 

  45. Van Lenthe, E., Baerends, E. J. & Snijders, J. G. Relativistic regular two-component Hamiltonians. J. Chem. Phys. 99, 4597–4610 (1993).

    Article  Google Scholar 

  46. Greer, R. D. M. et al. Structure and characterization of an americium bis(O,O′-diethyl)dithiophosphate complex. Inorg. Chem. 59, 16291–16300 (2020).

    Article  CAS  PubMed  Google Scholar 

  47. Gaiser, A. N. et al. Creation of an unexpected plane of enhanced covalency in cerium(III) and berkelium(III) terpyridyl complexes. Nat. Commun. 12, 7230 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  48. Ramanantoanina, H. LFDFT—a practical tool for coordination chemistry. Computation 10, 70 (2022).

    Article  CAS  Google Scholar 

  49. Ramanantoanina, H., Urland, W., Cimpoesu, F. & Daul, C. The angular overlap model extended for two-open-shell f and d electrons. Phys. Chem. Chem. Phys. 16, 12282–12290 (2014).

    Article  CAS  PubMed  Google Scholar 

  50. Judd, B. R. Optical absorption intensities of rare-earth ions. Phys. Rev. 127, 750–761 (1962).

    Article  CAS  Google Scholar 

  51. Ofelt, G. S. Intensities of crystal spectra of rare-earth ions. J. Chem. Phys. 37, 511–520 (1962).

    Article  CAS  Google Scholar 

  52. Glendening, E. D., Landis, C. R. & Weinhold, F. NBO 6.0: natural bond orbital analysis program. J. Comput. Chem. 34, 1429–1437 (2013).

    Article  CAS  PubMed  Google Scholar 

  53. Neese, F., Wennmohs, F., Becker, U. & Riplinger, C. The ORCA quantum chemistry program package. J. Chem. Phys. 152, 224108 (2020).

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgements

This research was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Heavy Elements Chemistry Program, under award no. DE-FG02-13ER16414.

Author information

Authors and Affiliations

  1. Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA

    Todd N. Poe, Brian M. Rotermund, Jacob Brannon, Zhuanling Bai, Nicholas Beck, Brian N. Long & Samantha Justiniano

  2. Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (INE), Karlsruhe, Germany

    Harry Ramanantoanina

  3. Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, USA

    Joseph M. Sperling, Hannah B. Wineinger, Benjamin Scheibe, Thomas E. Albrecht-Schönzart & Cristian Celis-Barros

Authors
  1. Todd N. Poe
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Harry Ramanantoanina
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Joseph M. Sperling
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Hannah B. Wineinger
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Brian M. Rotermund
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Jacob Brannon
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Zhuanling Bai
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Benjamin Scheibe
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Nicholas Beck
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Brian N. Long
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Samantha Justiniano
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Thomas E. Albrecht-Schönzart
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Cristian Celis-Barros
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

T.N.P., J.M.S., H.B.W., B.M.R., B.S., N.B., B.N.L., S.J. and T.E.A.-S. contributed to the conception and execution of the synthetic, spectroscopic, and crystallographic studies reported in this manuscript. T.N.P., J.M.S., H.B.W., B.M.R., J.B., Z.B., N.B. and B.N.L. contributed to the recycling and purification of 249Cf between experiments. H.R. and C.C.-B. carried out the computational studies. All authors discussed and co-wrote the manuscript.

Corresponding authors

Correspondence to Thomas E. Albrecht-Schönzart or Cristian Celis-Barros.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Chemistry thanks the anonymous reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Canonical molecular orbital energy diagram.

The orbital splitting obtained from spin-orbit CASSCF calculations, CAS(10,12), is consistent with a pseudo-D6h. Molecular orbitals in the active space are shown. The predicted spin-orbit ground state corrected by dynamic correlation is 72% 5I8 and 12% 3K8 (plus additional smaller contributions).

Extended Data Fig. 2 LFDFT absorption spectroscopy of [CfII(18-crown-6)(H2O)2(CH3CN)]2-.

Calculated absorption spectrum using the LFDFT approach, where a) the calculated intensities of the 5f→6d transitions obscure most of the 5f→5f transitions. The inset corresponds to the most intense 5f→5f transition consistent with the experimental spectrum. b) The 5f→5f transitions were zoomed in and the lowest lying states assigned. It is clear that the low intensity transitions J = 5 and J = 2 are significantly affected by the ∆S = 0 selection rule, and that there is strong J-mixing (bracketed in bold).

Source data

Extended Data Fig. 3 Solid-state absorption spectrum of [CfII(18-crown-6)(H2O)2(CH3CN)][CfIII(18-crown-6)(H2O)(CH3CN)I]I2.

The solid-state absorption spectra for crystals [CfII(18-crown-6)(H2O)2(CH3CN)][CfIII(18-crown-6)(H2O)(CH3CN)I]I2 collected at room temperature (green) and 93.15 K (black) possess similar features in the UV region to the broadband features observed in the solution absorption spectrum containing [Cf(18-crown-6)]3+ presented in Fig. 3.

Source data

Extended Data Fig. 4 Crystal structure of [Am(cis-syn-cis-dicyclohexano-18-crown-6)(H2O)(CH3CN)I]I2 • CH3CN and associated bond lengths.

a) and b) Preparation of AmI3 • nH2O (n ≤ 6) can be performed using the same methods reported for CfI3 • nH2O (n ≤ 6). Reaction of AmI3 • nH2O (n ≤ 6) with dicyclohexano-18-crown-6 and [NBu4][BPh4] in acetonitrile yields crystals of [Am(cis-syn-cis-dicyclohexano-18-crown-6)(H2O)(CH3CN)I]I2 • CH3CN after slow vapor diffusion of diethyl ether. (a) Features a view of the isolated metal complex showing the ligands in apical positions, while (b) shows the coordination of the dicyclohexano-18-crown-6 molecule in the equatorial plane of the molecule. c) A table of bond lengths for the metal complex is provided for comparison with the Cf complexes reported here, as well as similar Am complexes reported in the literature.

Extended Data Fig. 5 Solid-state absorption spectrum of [Am(cis-syn-cis-dicyclohexano-18-crown-6)(H2O)(CH3CN)I]I2 • CH3CN.

Solid-state absorption measurements of [Am(cis-syn-cis-dicyclohexano-18-crown-6)(H2O)(CH3CN)I]I2 • CH3CN yield characteristic 5f→5f transitions exhibited by this compound, namely group E transitions (7F6) at 19,763 cm−1 and hypersensitive group H transitions (5L6) at 12,207 cm−1.

Source data

Extended Data Fig. 6 Geometry optimization structure of the Cf mixed valent compound.

Depiction of the 13 iodide anions considered in the geometry optimization of the [CfII(18-crown-6)(H2O)2(CH3CN)][CfIII(18-crown-6)(H2O)(CH3CN)I]I2 complexes. Their positions were kept fixed in the optimization process.

Extended Data Fig. 7 Potential energy surfaces of the three possible assignments for apical ligands.

a) [CfIII(18-crown-6)(H2O)(CH3CN)(OH)]2- b) [CfII(18-crown-6)(H2O)2(CH3CN)]2- and c) [CfIII(18-crown-6)(H2O)(CH3CN)I]2-. Energies correspond to relative energies with respect to their corresponding minimum values in kJ/mol. Solid lines correspond to data fitting curves using quartic functions (R2 = 1 for each case). Distances at the minimum energy value are given for each case.

Source data

Supplementary information

Supplementary Information

Supplementary figs. 1–5, discussion and tables 1 and 2.

Supplementary Data 1

Source data for plots.

Supplementary Data 2

Crystal structure of Cf(18-crown-6)I2.

Supplementary Data 3

Crystal structure containing [Cf(18-crown-6)(H2O)2(CH3CN)][CfI(18-crown-6)(H2O)(CH3CN)I]2+.

Supplementary Data 4

Crystal structure of [Am(cis-syn-cis-dicyclohexano-18-crown-6)(H2O)(CH3CN)I]I2•CH3CN.

Supplementary Data 5

Crystal structure of Dy(18-crown-6)I2.

Source data

Source Data Fig. 4

Source data for plots.

Source Data Fig. 5

Source data for plots.

Source Data Extended Data Fig. 2

Source data for plots.

Source Data Extended Data Fig. 3

Source data for plots.

Source Data Extended Data Fig. 5

Source data for plots.

Source Data Extended Data Fig. 7

Source data for plots.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Poe, T.N., Ramanantoanina, H., Sperling, J.M. et al. Isolation of a californium(II) crown–ether complex. Nat. Chem. 15, 722–728 (2023). https://doi.org/10.1038/s41557-023-01170-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41557-023-01170-9

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing