NaCrO2
sodium chromite · sodium chromium dioxide
NaCrO2 is a stable, layered semiconducting oxide primarily investigated for its role as a cathode material in sodium-ion battery technology.
About sodium chromite
NaCrO2 belongs to the class of layered sodium transition-metal oxides, characterized by a semiconducting electronic structure. Its position on the convex hull indicates it is a thermodynamically stable phase, making it a robust subject for structural and electrochemical investigation.
This material is primarily studied for its potential in sodium-ion battery architectures. Due to its layered geometry, it facilitates the migration of sodium ions, which is a critical requirement for high-performance rechargeable energy storage systems.
Key Properties
Cross-validated computational properties for sodium chromite, aggregated across 3 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of NaCrO2. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for NaCrO2, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| R-3m (No. 166) | trigonal | 3.02 | 0.0000 | -7.478 | 4.36 |
| — | — | 2.87 | 0.0000 | -2.333 | — |
| R-3m (No. 166) | trigonal | 1.20 | 0.0000 | -2.103 | — |
| — | — | 2.87 | 0.0009 | -2.332 | — |
| — | — | 2.90 | 0.0015 | -2.332 | — |
| — | — | 2.83 | 0.0148 | -2.319 | — |
| — | — | 1.36 | 0.1012 | -2.232 | — |
| — | — | 1.10 | 0.2131 | -2.120 | — |
| — | — | 1.09 | 0.2133 | -2.120 | — |
| — | — | 1.10 | 0.2149 | -2.118 | — |
| R-3m (No. 166) | trigonal | 0.00 | 0.2460 | -1.857 | — |
| P6/mmm (No. 191) | hexagonal | 0.71 | 1.1195 | -6.359 | 1.37 |
Synthesis Routes
Literature-extracted synthesis procedures targeting NaCrO2.
Applications
Where sodium chromite is used.
Frequently Asked Questions
Common questions about sodium chromite, answered from cross-validated data.
What is NaCrO2?
NaCrO2 is a stable, layered semiconducting oxide primarily investigated for its role as a cathode material in sodium-ion battery technology.
What is NaCrO2 used for?
What is the band gap of NaCrO2?
Is NaCrO2 a metal, semiconductor, or insulator?
Is NaCrO2 thermodynamically stable?
What is the crystal structure of NaCrO2?
What is the density of NaCrO2?
How many polymorphs of NaCrO2 are known?
How is NaCrO2 synthesized?
What elements does NaCrO2 contain?
Where does the data for NaCrO2 come from?
How It Compares
Within the layered sodium transition-metal oxides class.
Within the family of layered sodium transition-metal oxides, NaCrO2 offers a distinct electrochemical profile compared to siblings like NaCoO2 or NaNiO2. While many of its counterparts are extensively utilized in commercial battery development, NaCrO2 serves as a vital benchmark for understanding transition-metal redox behavior and structural stability in sodium-based intercalation systems.
Related Compounds
Other Layered Sodium Transition-Metal Oxides in the database.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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