A family of uranyl oxide hydrate phases with bivalent cations [M^II(H₂O)₄][(UO₂)₃O₃(OH)₂]·H₂O (M^II– Mn, Co, Ni, Zn): synthesis, characterization and chemical stability in aqueous solutions

Abstract

A series of new uranium compounds [MII(H2O)3][(UO2)3O3(OH)2]·2H2O (MII – Mn, Co, Ni, Zn) were synthesized for binding radionuclides in the environment and nuclear fuel cycle.

Exploring the influence of pH on the structural intricacies of uranium oxide hydrates containing both Cd(ii) and K(i) ions

“…Whilst uncommon, similar results have been found in other synthetic UOH systems. 9,21,30,44 14 2.830(7) U2-O3 7 2.301(7) Cd1-O2 9 2.257(6) Cd2-O5 2.544(7) K1-O6 15 2.775(8) U2-O3 6 2.397 (7) Cd1-O2 7 2.257(6) Cd2-O5 13 2.544(7) K1-O6 6 2.775(8) 13 2.947(15) K2-O8 7 3.102(15) K3-O4 18 2.852(17) K2-O8 4 3.102(15) K3-O4 2.852(17) K2-O17 14 2.726(15) K3-O7 18 2.931(15) K2-O17 6 2.726(15) K3-O7 2.931(15) K2-O18 2.685(16) K3-O8 3.238(16) K2-O18 15 2.685(16) K3-O8 18 3.238(16) K2-O20 16 2.714(16) K3-O18 3 2.888(16) K2-O20 17 2.714(16) K3-O18 4 2.888( 16)…”

“…Given their abundance in the environment, the understanding of the alteration chemistry of UO 2 systems in the presence of transition metals is essential. With only a handful of transition metal-containing UOH materials reported, 14,18,30 there exists a clear need for further study in this area.…”

“…10 The importance of understanding these materials has given rise to dozens of UOH-based minerals, 1,10,11 with more than a dozen synthetic UOH compounds having also been identified. [12][13][14] One of the main factors differentiating these materials is the secondary metal ion which lies between the uranyl oxide hydroxide layers, with a diverse range including alkali, 15 alkaline earth, 16 heavy metals, 17 transition metals 18 and lanthanides 19 having been reported thus far.…”

Investigation of uranium oxide hydrates with barium(ii) ions: structural diversity, uranium valences and implications

“…22 Hydrothermal synthesis in the laboratory has been used to assist the formation of the UOH compounds in a simulated natural environment. To date, more than two dozen of synthetic UOH compounds have been made with interlayer cations including alkali, 23,24 alkaline earth, 25,26 lead, 27 limited 3d transition metal [28][29][30] and lanthanide ions. [31][32][33][34] Complicating these UOH systems are a further number of compounds which have a slightly different structure where the apical oxygen of the uranyl ions on the layer shares the equatorial oxygen with an interlayer uranyl ion acting as a pillar, resulting in an open three-dimensional (3D) framework structure typically incorporating various cations in the framework channels.…”

Filling the gaps of uranium oxide hydrates with magnesium(ii) ions: unique layered structures and the role of additional sodium(i) ions

“…[19][20][21][22] In addition, the uranyl oxide hydroxide layer topologies for various UOH minerals have been comprehensively reviewed. 23 In addition, synthetic UOH materials with a wide range of secondary cations including alkali, 24,25 alkaline earth, [26][27][28][29] lead, 30 transition metals [31][32][33] and lanthanide ions [34][35][36] have been reported. Furthermore, synthetic UOH phases with interlayer anions are also possible, although less studied.…”