Syntheses, Structures, and Spectroscopic Properties of Plutonium and Americium Phosphites and the Redetermination of the Ionic Radii of Pu(III) and Am(III)

Abstract

A series of isotypic rare earth phosphites (RE = Ce(III), Pr(III), Nd(III), Pu(III), or Am(III)) with the general formulas RE(2)(HPO(3))(3)(H(2)O) along with a Pu(IV) phosphite, Pu[(HPO(3))(2)(H(2)O)(2)], have been prepared hydrothermally via reactions of RECl(3) with phosphorous acid. The structure of RE(2)(HPO(3))(3)(H(2)O) features a face-sharing interaction of eight- and nine-coordinate rare earth polyhedra. By use of the crystallographic data from the isotypic series along with data from previously reported isotypic series, the ionic radii for higher coordinate Pu(III) and Am(III) were calculated. The (VIII)Pu(III) radius was calculated as 1.112 ± 0.004 Å, and the (IX)Pu(III) radius was calculated to be 1.165 ± 0.002 Å. The (VIII)Am(III) radius was calculated as 1.108 ± 0.004 Å, and the (IX)Am(III) radius was calculated as 1.162 ± 0.002 Å.

Comparing the 2,2′‐Biphenylenedithiophosphinate Binding of Americium with Neodymium and Europium

“…The Am III bond lengths agree well with previously reported EXAFS data for Am III extracted with bis(2,4,4‐trimethylpentyl)dithiophosphinic acid, HS 2 P[C 8 H 17 ] 2 (Cyanex 301), into kerosene . A plot of the mean M−S bond lengths in the M[S 2 P( t Bu 2 C 12 H 6 )] 4 x− complexes (M=Eu, Nd, or Am: x= 1; M=U, Np: x= 0) versus the metal ionic radii (Figure ) showed a linear relationship for Eu III , Nd III , U IV , and Np IV . The data was fit with a line whose slope approached unity, 0.89(2), and whose y intercept [1.95(2) Å] was approximately equal to the S 2− ionic radius (1.84 Å) .…”

“…As HS 2 P( t Bu 2 C 12 H 6 ) is air‐ and moisture‐stable and soluble in common solvents, it provided an opportunity to compare and contrast the chemistry of minor actinide and lanthanide complexes with identical dithiophosphinate ligands. Herein, we compare the dithiophosphinate chemistry of Am III (5f 6 ) with that of its electronic congener Eu III (4f 6 ) and a size‐matched 4f analogue, Nd III (the ionic radii for Am III and Nd III are 1.109 and 1.108 Å) . The isolation of the tetrakis(4,4′‐di‐ tert ‐butyl‐2,2′‐biphenylenedithiophosphinato)metal(III) anions, M[S 2 P( t Bu 2 C 12 H 6 ] 4 1− (M=Am, Nd, or Eu), enabled the first single‐crystal measurement of an Am−S bond distance.…”

From Yellow to Black: Dramatic Changes between Cerium(IV) and Plutonium(IV) Molybdates

“…[4][5][6][7][8][9][10][11][12][13][14] Exploration of this field is filled with opportunity as there are only a few systems that have systematically spanned the lanthanide and actinide series such as the aquo-triflates, phosphonates, and phosphites. [15][16][17][18][19][20][21][22][23][24][25] It is in this objective we have chosen to explore the rare earth molybdates.…”

Origin of Selectivity of a Triazinyl Ligand for Americium(III) over Neodymium(III)

“…Nd III is often used as as tructural analogue of Am III because of their overlapping ionic radii. [8] Thus,i ti sn ot surprising that [Nd(EtBTP) 3 ][BPh 4 ] 3 ·3CH 3 CN and [Am(EtBTP) 3 ][BPh 4 ] 3 ·3CH 3 CN are isomorphous. These compounds crystallize with unusually high symmetry for molecular systems and are found to adopt tetragonal symmetry in space group I4 1 /a.…”

“…Likewise, f-f transitions involved in the experimental absorption spectra were assigned through the SO-CASw avef unctiona nd agree with those reported elsewhere (Table 1). [8,[30][31][32] Moreover,t he nature of the ground states is also different for both complexes. [ Nd(EtBTP) 3 ] 3 + possesses am ulticonfigurational quartet ground state, whereas [Am(EtBTP) 3 ] 3 + has am ultireference ground state, that is 78 %s eptet and 18 %q uintet.…”