Studies of californium(II) and (III) iodides

Wild, J. F.; Hulet, E.K.; Lougheed, R. W.; Hayes, W.N.; Peterson, J.R.; Fellows, R.L.; Young, J. P.

doi:10.1016/0022-1902(78)80157-2

Cited by 33 publications

(7 citation statements)

References 15 publications

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“…6 Whereas the Cf III dominates the chemistry of californium, 6 there are several known Cf II compounds, notably the dihalides CfCl 2 , 7 CfBr 2, 8 and CfI 2 . 9 Although Cf 2+ is not inherently stable in solution, its existence has been established by radiopolarography in acetonitrile 10 and in aqueous solutions. 11 The known solid state and solution chemistry of Cf, specifically the stability of the divalent oxidation state, closely parallels that of Sm.…”

Section: Introductionmentioning

confidence: 99%

Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii)

et al. 2016

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The divalent oxidation state is increasingly stable relative to the trivalent state for the later actinide elements, with californium the first actinide to exhibit divalent chemistry under moderate conditions. Although there is evidence for divalent Cf in solution and solid compounds, there are no reports of discrete complexes in which Cf(II) is coordinated by anionic ligands. Described here is the divalent Cf methanesulfinate coordination complex, Cf(II)(CH3SO2)3(-), prepared in the gas phase by reductive elimination of CH3SO2 from Cf(III)(CH3SO2)4(-). Comparison with synthesis of the corresponding Sm and Cm complexes reveals reduction of Cf(III) and Sm(III), and no evidence for reduction of Cm(III). This reflects the comparative 3+/2+ reduction potentials: Cf(3+) (-1.60 V) ≈ Sm(3+) (-1.55 V) ≫ Cm(3+) (-3.7 V). Association of O2 to the divalent complexes is attributed to formation of superoxides, with recovery of the trivalent oxidation state. The new gas-phase chemistry of californium, now the heaviest element to have been studied in this manner, provides evidence for Cf(II) coordination complexes and similar chemistry of Cf and Sm.

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Section: Introductionmentioning

confidence: 99%

Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii)

et al. 2016

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“…30,31 Based on reported absorption data for Cf 2+ binary halides, it is anticipated that compounds containing Cf 2+ would also exhibit characteristic 5f→5f transitions. 20,[32][33][34] However, the broadband features observed in the experimental absorption spectra reported here are, in fact, 5f→6d transitions (Figure 4), and there is a notable lack of expected 5f→5f transitions. For comparison with the experimental data presented here as well as relevant literature data, Ligand-field DFT calculations were used to predict the absorption spectrum for this system (Figure 5).…”

Section: Resultsmentioning

confidence: 86%

“…For example, radiolysis products rapidly reduce Bk IV to Bk III , but instead oxidize Cf II I2 to Cf III OI via the stunning -particle induced abstraction of oxide from silica reaction vessels. 19,20 The latter provides an excellent illustration of the energetic differences between nuclear and chemical reactions. Taken together, there are two hurdles to overcome to successfully isolate a Cf II complex.…”

Section: Introductionmentioning

confidence: 99%

Isolation of a Californium(II) Crown-Ether Complex

Poe

Ramanantoanina

Sperling

et al. 2022

Preprint

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Californium (Z = 98) is the first member of the actinide series displaying metastability of the 2+ oxidation state. Understanding the origin of this chemical behavior requires characterizing Cf(II) materials, but isolating a complex with this state has remained elusive. The source of its inaccessibility arises from the intrinsic challenges of manipulating this unstable element as well as a lack of suitable reductants that do not reduce Cf(III) to Cf(0). Herein we show that a Cf(II) crown-ether complex, Cf(18-crown-6)I2, can be prepared using an Al/Hg amalgam as a reductant. While spectroscopic evidence shows that Cf(III) can be quantitatively reduced to Cf(II), rapid radiolytic re-oxidation back to the Cf(III) parent occurs and co-crystallized mixtures of Cf(II) and Cf(III) complexes are isolated if the crystallization is not conducted over 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 remarkably weak 5f→5f transitions and an absorption spectrum dominated by 5f→6d transitions.

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“…30,31 Based on reported absorption data for Cf 2+ binary halides, it is anticipated that compounds containing Cf 2+ would also exhibit characteristic 5f→5f transitions. 20,[32][33][34] However, the broadband features observed in the experimental absorption spectra reported here are, in fact, 5f→6d transitions (Figure 4), and there is a notable lack of expected 5f→5f transitions. For comparison with the experimental data presented here as well as relevant literature data, Ligand-eld DFT calculations were used to predict the absorption spectrum for this system (Figure 5).…”

Section: Resultsmentioning

confidence: 86%

Isolation of a Californium(II) Crown-Ether Complex

Poe

Ramanantoanina²,

Sperling

et al. 2022

Preprint

View full text Add to dashboard Cite

Californium (Z = 98) is the first member of the actinide series displaying metastability of the 2 + oxidation state. Understanding the origin of this chemical behavior requires characterizing CfII materials, but isolating a complex with this state has remained elusive. The source of its inaccessibility arises from the intrinsic challenges of manipulating this unstable element as well as a lack of suitable reductants that do not reduce CfIII to Cf0. Herein we show that a CfII crown-ether complex, Cf(18-crown-6)I2, can be prepared using an Al/Hg amalgam as a reductant. While spectroscopic evidence shows that CfIII can be quantitatively reduced to CfII, rapid radiolytic re-oxidation back to the CfIII parent occurs and co-crystallized mixtures of CfII and CfIII complexes are isolated if the crystallization is not conducted over 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 remarkably weak 5f→5f transitions and an absorption spectrum dominated by 5f→6d transitions.

show abstract

Studies of californium(II) and (III) iodides

Cited by 33 publications

References 15 publications

Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii)

Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii)

Isolation of a Californium(II) Crown-Ether Complex

Isolation of a Californium(II) Crown-Ether Complex

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