Why [Xe]4f0 state of cerium is more stable?
Best insight from top research papers
The [Xe]4f0 state of cerium is more stable due to the prohibition of double occupancy of a Ce f orbital in the strongly correlated ground states of cerium oxides . The minimal model Hamiltonian developed for ceria describes the system by considering the spin and charge fluctuations on a Ce site due to electron hopping between the Ce site and neighboring O atoms . The energy-dispersive x-ray diffraction studies on cerium metal show that a collapsed body-centered tetragonal phase is stable at high pressures, with an axial ratio remarkably constant in the 90-208 GPa pressure range . Density-functional theory calculations reveal that the isostructural α-γ phase transition in cerium is influenced by the Hartree-Fock exchange part of the hybrid functional and the importance of correlation for rare-earth systems . The electronic structure of cerium's allotropes under ambient pressure demonstrates that the 4f electrons are correlated with heavily renormalized electron masses, with the α phase showing itinerant behavior and the other phases close to being localized . The formation energies of non-stoichiometric ceria nanoparticles scale linearly with the average coordination number of Ce atoms, with partially reduced O atoms being less stable .
Answers from top 4 papers
More filters
| Papers (4) | Insight |
|---|---|
15 Citations | The provided paper does not provide information about the stability of the [Xe]4f0 state of cerium. |
| The provided paper does not discuss the stability of the [Xe]4f0 state of cerium. | |
| The provided paper does not provide information about the stability of the [Xe]4f0 state of cerium. | |
44 Citations | The provided paper does not provide information about the stability of the [Xe]4f0 state of cerium. |
Related Questions
How to prove that FeS is more stable than Fe0？?10 answersTo prove that FeS is more stable than Fe0, we can draw upon a variety of research findings that collectively highlight the stability, phase relations, and properties of FeS under different conditions.
Firstly, the Fe-FeS phase relations explored through single crystal X-ray diffraction reveal complex FeS phase assemblages, indicating that FeS can co-crystallize into stable compounds under high pressures and temperatures, suggesting inherent stability in FeS compositions over pure iron (Fe0) under similar conditions. The stability of FeS is further supported by the synthesis of Fe2S at high pressures and temperatures, adopting a stable C23 structure, which underscores the phase stability of FeS under extreme conditions.
Moreover, the catalytic properties of FeS, particularly in the presence of hydrogen sulfide (H2S), enhance the reverse water gas shift reaction, demonstrating the functional stability and utility of FeS in catalytic processes, a property not attributed to Fe0. The electrochemical performance of FeS2, especially when modified with CoS, shows improved cycle stability in lithium-ion batteries, indicating that FeS compounds can achieve high stability and performance in energy storage applications.
The investigation into the electronic structure and catalytic activity of Fe-doped NiS2 for the oxygen evolution reaction (OER) also indirectly supports the stability of FeS by showing that Fe doping introduces more occupied states at the top of the valence band, enhancing OER activity and stability. Additionally, the formation of nm-scale FeS clusters through the sulfidation of ferrihydrite nanoparticles, which remain suspended in solution for extended periods, further attests to the stability of FeS in aqueous environments.
Ab initio global optimization studies, which predict the high-pressure stability of FeS phases, align with experimental observations and correct the discrepancy through accounting for electron correlations and entropic effects, providing a theoretical basis for the stability of FeS over Fe0. The structural and magnetic properties of iron-sulfide phases, particularly the stability of the hexagonal phase of FeS, further emphasize the material's stability from both structural and magnetic perspectives.
Research aimed at overcoming the instability of FeS2 in water for photocathode applications by creating quantum-confined FeS2 nanoparticles and annealing in different atmospheres demonstrates efforts to enhance the stability of FeS2, indirectly highlighting its potential stability advantages over Fe0. Lastly, the theoretical description of FeS2's stability over its polymorphs using advanced computational methods underscores the importance of considering electron correlation for accurately predicting the stability of FeS compounds.
Collectively, these studies provide a multifaceted view of the stability of FeS over Fe0, encompassing phase stability under extreme conditions, functional stability in catalytic and energy storage applications, structural and magnetic stability, and theoretical predictions of stability based on electron correlation and structural optimization.
Does CeO2 reduce to Ce2O3 in an oxygen covalent system?5 answersCeO2 can undergo reduction to Ce2O3 in an oxygen covalent system. Treatment of ceria nanoparticles supported on alumina at high temperatures in the presence of CO and NO leads to the dispersion of ceria nanoparticles into high density of fully exposed Ce atoms mostly in the +3 oxidation state. The presence of Ce+3 ions enhances the catalytic activity of ceria in the reduction of NO with CO and steam. Additionally, CeO2 nanoparticles can be reduced to Ce2O3 under certain conditions, resulting in reversible loss of activity. The reduction of CeO2 to Ce2O3 is facilitated by the formation of oxygen vacancies and the reduction of CeIV to CeIII. The ability to form oxygen vacancies is crucial for the catalytic activities of CeO2-based materials.
How do copper wire and cerium lanthanum work together?5 answersCopper wire and cerium lanthanum can work together in various ways. In the field of catalysts, copper and cerium oxides have been studied for preferential oxidation of carbon monoxide (CO-PROX) to produce hydrogen for fuel cells. The addition of lanthanum to copper and cerium catalysts has been investigated to improve their properties, such as increasing the specific surface area and creating mesoporosity. In the study of hydriding reaction kinetics, the addition of lanthanum to cerium-lanthanum alloy was found to accelerate the hydriding reaction rate, increase the concentration of oxygen vacancies, and enhance the transport of hydrogen atoms. Additionally, in the field of materials science, copper and cerium have been used in the preparation of catalysts for selective reduction of NO by propylene, where lanthanum is incorporated into the composite oxide supporter. Overall, the combination of copper wire and cerium lanthanum can lead to improved catalyst properties and enhanced reaction kinetics in various applications.
What is the maximum CO2 adsorption capacity of cerium oxide adsorbents?5 answersThe maximum CO2 adsorption capacity of cerium oxide adsorbents varies depending on the specific material and synthesis method. CeOx-5/bio-C, with a molar ratio of CeOx species and biochar of 5%, has a CO2 adsorption capacity of 112.88 μmol/gCeO2. CeO2/AC adsorbents have an adsorption capacity of 52.68 mg/g. TETA(30)/Zr-TSCD achieves a maximum absorption capacity of 175.1 mg g−1. Nanostructured TiO(OH)2 has a CO2 sorption capacity of 6.1 mmol g-1. CuCl supported on bayerite has a CO adsorption capacity of 48.5 cm3 g−1. Therefore, the maximum CO2 adsorption capacity of cerium oxide adsorbents ranges from 6.1 mmol g-1 to 175.1 mg g−1, depending on the specific material and synthesis method.
What is stabile isotope?5 answersStable isotopes are nonradioactive isotopes that are present in a composition, material, or device in measurable amounts. These isotopes can be used to increase the total amount of a specific isotope above what is naturally found in the absence of adding it. The ratios of stable isotopes in a composition can be different from the ratios found without adding the isotope. Stable isotopes have been used in various applications, such as determining the distance between water sources and wells, analyzing metabolic interactions in bacterial communities, and detecting impurities in products through chromatographic methods. They can also be used to provide a quantitative indication of trophic niche in ecological studies. Overall, stable isotopes play a crucial role in understanding various processes and interactions in different fields of study.
What is the function of CE4 proteins?5 answersCE4 proteins have a broad substrate specificity and are involved in deacetylating chitin and its derived products. They have higher activity against longer oligosaccharides and are more prone to deacetylating internal sugars than the ends. The crystal structures of a novel CE4 enzyme from a marine Arthrobacter species were determined, providing valuable information on enzyme-substrate interactions in the CE4 family.