Periodic Trends in Actinide Phosphonates: Divergence and Convergence between Thorium, Uranium, Neptunium, and Plutonium Systems

Abstract

The hydrothermal reactions of both PuO(2)(2+) and PuO(2) with phosphonates results in the formation of Pu(IV) phosphonates. Pu(CH(3)PO(3))(2), Pu[CH(2)(PO(3))(2)](H(2)O), and UO(2)Pu(H(2)O)(2)[CH(2)(PO(3))(PO(3)H)](2) have been isolated from these reactions and structurally characterized. Pu(CH(3)PO(3))(2) contains six-coordinate Pu(IV) and adopts a structure closely related to that of alpha-Zr(HPO(4))(2). Pu[CH(2)(PO(3))(2)](H(2)O) forms a novel three-dimensional network with seven-coordinate Pu(IV) and chelating/bridging [CH(2)(PO(3))(2)](4-) anions. The heterobimetallic U(VI)/Pu(IV) diphosphonate, UO(2)Pu(H(2)O)(2)[CH(2)(PO(3))(PO(3)H)](2), also forms a three-dimensional network. To complete the An[CH(2)(PO(3))(2)](H(2)O)(n) (An = Th, U, Np, Pu; n = 1, 2) and UO(2)An(H(2)O)(2)[CH(2)(PO(3))(PO(3)H)](2) series, Th[CH(2)(PO(3))(2)](H(2)O)(2) and UO(2)Th(H(2)O)(2)[CH(2)(PO(3))(PO(3)H)](2) have also been prepared. These compounds are isostructural with their Np(IV) analogues.

Using Phosphonates to Probe Structural Differences Between Transuranium Elements and Their Proposed Surrogates

“…[13,16] In all cases, the metal ions are in the tetravalent oxidation state. In some cases the synthetic chemistry is not as consistent between elements as would be desired.…”

Structural and spectroscopic characterization of two new layered uranyl(VI) p-xylenediphosphonate compounds synthesized via ionothermal method

“…The crystal chemistry of actinide phosphonates is an important subfield of metal phosphonates, where major attention was paid to uranium [13][14][15][16][17][18][19] and thorium [20][21][22], with only a few neptunium [22][23][24], plutonium [25][26][27][28], and americium [28] complexes. Layered structure is always observed in uranyl phosphonates, due to the nature of equatorial coordination sites (from four to six) of the uranyl ion, leading the structure to 2D topologies [19,[29][30][31][32][33][34].…”

Effects of Te(IV) Oxo-Anion Incorporation into Thorium Molybdates and Tungstates

“…11,12 In the midst of numerous actinide compounds, one of the poorly investigated families is the actinide tellurites. It is also the case for thorium where phosphate, 13,14 molybdate, 15,16 and silicate 17 compounds have been mostly been studied. The actinide tellurite family was first encountered from a handful of minerals including cliffordite (UO 2 (Te 3 O 7 )), 18 moctezumite (PbUO 2 (TeO 3 ) 2 ), 19 and schmitterite (UO 2 (TeO 3 )).…”