Related Experiment Video
Updated: Aug 14, 2025
08:15
Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups
Published on: February 11, 2012
14.1K
Local Structure in α-BIMEVOXes (ME = Ge, Sn)
Yajun Yue1,2, Aleksandra Dzięgielewska3, Man Zhang4
1Department of Chemistry, Queen Mary University of London, Mile End Road, LondonE1 4NS, United Kingdom.
Chemistry of Materials : a Publication of the American Chemical Society
|January 16, 2023
Summary
BISMUTH VANADATE (BIMEVOX) oxide ion conductors exhibit high conductivity due to their local defect structures. Differences in substituent cation coordination (Ge, Sn) significantly influence vacancy distribution and overall ionic conductivity.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Crystallography
Background:
- BISMUTH VANADATE (BIMEVOX) materials are recognized for their excellent oxide ion conductivity at low and intermediate temperatures.
- High ionic conductivity in these materials is strongly linked to their specific local defect structures.
- Understanding the local atomic arrangements and defect distributions is crucial for optimizing their performance.
Purpose of the Study:
- To investigate the local structures of two BIMEVOX compositions: Bi2V0.9Ge0.1O5.45 (BIGEVOX10) and Bi2V0.95Sn0.05O5.475 (BISNVOX05).
- To correlate local structural features and defect ordering with ionic conductivity.
- To elucidate the role of substituent cations (Germanium and Tin) in determining local coordination and vacancy distribution.
Main Methods:
- Total neutron and X-ray scattering techniques were employed to analyze local atomic structures.
- Dielectric permittivity measurements and density functional calculations with machine learning were used to assess ferroelectric properties.
- Reverse Monte Carlo (RMC) analysis, 51V solid-state NMR spectroscopy, and impedance spectroscopy were utilized to characterize local coordination, vacancy distribution, and ionic conductivity.
Main Results:
- Both compositions exhibit an ordered α-phase at 25 °C and a disordered γ-phase at 700 °C.
- Reverse Monte Carlo analysis revealed distinct coordination preferences for Ge (tetrahedral) and Sn (octahedral in α-phase, tetrahedral in γ-phase).
- Significant differences in oxide ion vacancy distributions were observed between BIGEVOX10 and BISNVOX05, attributed to substituent cation preferences.
- Both materials demonstrated high ionic conductivity (order of 10-1 S cm-1 at 600 °C).
Conclusions:
- The local structure and defect ordering in BIMEVOX materials are critically influenced by the nature of the substituent cation.
- The observed differences in vacancy distribution directly impact the ionic conductivity of these promising oxide ion conductors.
- These findings provide valuable insights for the rational design of advanced BIMEVOX-based electrolytes for electrochemical applications.
More Related Videos
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
9.3K
14:44Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
9.7K
Related Concept Videos
01:09¹H NMR: Pople Notation
1.9K
The Pople nomenclature system classifies spin systems based on the difference between their chemical shifts. Coupled spins are denoted by capital letters with subscripts indicating the number of equivalent nuclei. When the coupled nuclei have well-separated chemical shifts, they are assigned letters that are far apart in the alphabet, such as A and X. When the difference in chemical shifts is small, coupled nuclei are named using adjacent letters of the alphabet (AB, MN, or XY).
A proton...
A proton...
1.9K
01:03¹H NMR Chemical Shift Equivalence: Homotopic and Heterotopic Protons
2.5K
Protons in identical electronic environments within a molecule are chemically equivalent and have the same chemical shift. The replacement test is a useful tool to identify chemical equivalence and predict NMR spectra. A substituent replaces each of the protons being examined and the resulting molecules are compared. If the same molecule is obtained, the protons are equivalent or homotopic. Replacement of any hydrogens in ethane by chlorine yields chloroethane because all six protons are...
2.5K
00:58¹H NMR Chemical Shift Equivalence: Enantiotopic and Diastereotopic Protons
1.9K
Replacing each alpha-hydrogen in chloroethane by bromine (or a different functional group) yields a pair of enantiomers. Such protons are called prochiral or enantiotopic and are related by a mirror plane. Enantiotopic protons are chemically equivalent in an achiral environment. Because most proton NMR spectra are recorded using achiral solvents, enantiotopic hydrogens yield a single signal.
In chiral compounds such as 2-butanol, replacing the methylene hydrogens at C3 produces a pair of...
In chiral compounds such as 2-butanol, replacing the methylene hydrogens at C3 produces a pair of...
1.9K
01:13¹H NMR: Complex Splitting
1.3K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.3K
01:19Mass Spectrometry of Amines
4.3K
In mass spectroscopy, amines undergo fragmentation to give parent ions with odd molecule weights. This observed mass spectrum follows the nitrogen rule: a molecule with an odd number of nitrogen atoms produces a parent ion with an odd molecular weight. The remaining fragments have an even mass.
Amines undergo fragmentation through α cleavage, producing nitrogen-containing cations—iminium ions—and alkyl radicals. Mass spectra of aromatic and cyclic aliphatic amines exhibit...
Amines undergo fragmentation through α cleavage, producing nitrogen-containing cations—iminium ions—and alkyl radicals. Mass spectra of aromatic and cyclic aliphatic amines exhibit...
4.3K
01:19Structure of Amines
2.6K
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’...
2.6K