Related Experiment Video
Updated: Oct 31, 2025
Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Charge Localization and Magnetic Correlations in the Refined Structure of U3O7
Gregory Leinders1, Gianguido Baldinozzi2, Clemens Ritter3
1Belgian Nuclear Research Centre (SCK CEN), Institute for Nuclear Materials Science, Boeretang 200, B-2400 Mol, Belgium.
This study refines the atomic structure of Uranium oxide U3O7, revealing a mixed-valence state with localized charges and magnetic uranium atoms. Calculations predict semiconducting behavior and a charge-transfer insulator state.
Area of Science:
- Solid-state chemistry
- Materials science
- Nuclear materials
Background:
- Uranium oxides exhibit complex electronic and magnetic properties.
- Understanding mixed-valence compounds is crucial for nuclear fuel applications.
Purpose of the Study:
- To refine the atomic structure of U3O7 using neutron scattering.
- To investigate the interplay between charge localization and magnetism in U3O7.
- To determine the valence states and magnetic moments of uranium ions.
Main Methods:
- High-resolution neutron scattering for structural refinement.
- Electronic structure calculations including spin-orbit interactions.
- Hirshfeld charge analysis.
Main Results:
- A detailed crystallographic model for U3O7 with distorted oxygen cuboctahedra.
- Evidence of charge localization and magnetic moments on uranium atoms.
- U3O7 is predicted to be a semiconductor (0.32 eV band gap) and a charge-transfer insulator.
- Valence distribution: 24/60 U(IV), 32/60 U(V), 4/60 U(VI).
- U(IV) and U(V) ions carry noncollinear magnetic moments, leading to canted ferromagnetic order.
Conclusions:
- The structure of U3O7 exhibits long-range order with specific uranium coordination environments.
- A strong correlation exists between charge distribution and magnetic properties.
- U3O7 displays distinct electronic and magnetic characteristics compared to UO2.
More Related Videos
12:05U2O5 Film Preparation via UO2 Deposition by Direct Current Sputtering and Successive Oxidation and Reduction with Atomic Oxygen and Atomic Hydrogen
Published on: February 21, 2019
06:49Radio Frequency Magnetron Sputtering of GdBa2Cu3O7âˆ'ÃŽ ´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates
Published on: April 12, 2019
Related Concept Videos
02:42Valence Bond Theory
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
02:42Ionic Crystal Structures
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
02:33Lattice Centering and Coordination Number
Types of Unit Cells
Imagine taking a large number of identical...