Incorporating Transition Metal Ions into Uranium Oxide Hydrates: The Role of Zn(II) and the Effect of the Addition of Cs(I) Ions.

The synthesis of two zinc-bearing uranium oxide hydrate (UOH) materials has been achieved, and their crystal structures, obtained via single-crystal X-ray diffraction using synchrotron radiation, and additional structural and spectroscopic properties are reported herein. Although both structures incorporate Zn cations, the two differ significantly. The compound Zn(OH)(HO)[(UO)UO(HO)] (), forming a framework-type structure in the 1̅ space group, was composed of β-UO layers pillared by uranyl polyhedra, with the Zn cations incorporated within the framework channels.

Capturing ammonium nitrate in a synthetic uranium oxide hydrate phase: revealing the role of ammonium ions and anion inclusions.

Although uranium oxide hydrate (UOH) minerals and synthetic phases have been extensively studied, the role of ammonium ions in the formation of UOH materials is not well understood. In this work, the stabilization of a synthetic UOH phase with ammonium ions and the inclusion of ammonium nitrate were investigated using a range of structural and spectroscopic techniques. Compound (NH)(NO)[(UO)O(OH)] (U-N1) crystallises in the orthorhombic 2 space group, having a layered structure with typical α-UO type layers and interlayer (NH) cations as well as (NO) anions.

Uranium Oxide Hydrate Frameworks with Dy(III) or Lu(III) Ions: Insights Into the Framework Structures With Lanthanide Ions.

Two uranium oxide hydrate frameworks (UOHFs) with either Dy or Lu ions, Dy(HO)[(UO)UO(OH)] (UOHF-Dy) or Lu(HO)[(UO)UO(OH)] (UOHF-Lu), were synthesized hydrothermally and characterized with a range of structural and spectroscopic techniques. Although SEM-EDS analysis confirmed the same atomic ratio of ~5.5 for U : Dy and U : Lu, they displayed different crystal morphologies, needles for UOHF-Dy in the orthorhombic C222 space group and plates for UOHF-Lu in the triclinic P-1 space group.

Exploring the influence of pH on the structural intricacies of uranium oxide hydrates containing both Cd(II) and K(I) ions.

We report the synthesis of two new dual-cation uranium oxide hydrate (UOH) materials, containing both Cd and K ions, along with their characterisation by means of single-crystal X-ray diffraction and a range of other structural and spectroscopic techniques. The materials were found to differ in structures, topology and uranium to cation ratios, with the layered UOH-Cd crystallising in a plate morphology and containing a U : Cd : K ratio of 3 : 1.5 : 1.

Uranium oxide hydrate frameworks with Er(III) or Y(III) ions: revealing structural insights leading to the low symmetry.

Two new mixed-valence uranium oxide hydrate frameworks (UOFs), incorporating either Er or Y ions, were successfully synthesised under hydrothermal conditions and characterised with single-crystal X-ray diffraction and a variety of other structural and spectroscopic techniques. Both frameworks are isostructural and crystallise in the triclinic 1̄ space group, consisting of β-UO type layers pillared by additional uranyl centres, with the Er/Y ions lying in the channels of the framework. SEM-EDS analysis found that both materials existed in plate-like morphologies, with a U:Er/Y ratio of 5.

Coupling Postsynthetic High-Temperature Oxidative Thermolysis and Thermal Rearrangements in Isoreticular Zinc MOFs.

Herein, we report coupling high temperature postsynthetic modifications (PSMs) in metal-organic frameworks (MOFs). Thermo-reactive propargyloxy-functionalized zinc IRMOFs (isoreticular metal-organic frameworks) prepared from 2-(prop-2-yn-1-yloxy)-[1,1'-biphenyl]-4,4'-dicarboxylic acid (HbpdcOCHCCH) were investigated for their high-temperature postsynthetic rearrangement (PSR) chemistry to heterocyclic chromenes and benzofurans and then coupled to solid-gas reactions with molecular oxygen. The selectivity for the initial molecular rearrangements was found to be inverted in the porous MOF environment compared to conventional melt reactions of the ester compound MebpdcOCHCCH and proceeded far more easily than the solid-state transformation from HbpdcOCHCCH, showing the potential of MOFs to give rise to different chemistry.

Synthesis and Structure of Oxygen Deficient Lead-Technetium Pyrochlore, the First Example of a Valence V Technetium Oxide.

The structure of lead-technetium pyrochlore has been refined in space group with = 10.36584(2) Å using a combination of synchrotron X-ray and neutron powder diffraction data and confirmed via Electron Diffraction. The oxide is found to be oxygen deficient with a stoichiometry of PbTcO.