K3NiO2
K3NiO2 is a thermodynamically stable, semiconducting oxide material utilized in the study of oxygen-evolution catalysis.
About K3NiO2
K3NiO2 is a semiconducting oxide that holds a distinct position within the family of oxygen-evolution catalysts. Its status as a thermodynamically stable phase on the convex hull underscores its structural integrity, making it a subject of interest for researchers investigating robust catalytic materials for energy storage and conversion applications. The compound benefits from a well-documented structural profile, supported by multiple entries across major materials databases. Its electronic properties suggest potential utility in electrochemical systems where stable, semiconducting oxides are required to facilitate efficient oxygen-evolution reactions. By providing a stable framework for nickel-oxygen interactions, it serves as a foundational material for exploring advanced catalytic mechanisms.
Key Properties
Cross-validated computational properties for K3NiO2, aggregated across 5 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 K3NiO2. 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 K3NiO2, 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. |
|---|---|---|---|---|---|
| — | — | 1.80 | 0.0000 | -1.152 | — |
| P42/mnm (No. 136) | tetragonal | 0.00 | 0.0000 | -1.230 | — |
| P41212 (No. 92) | tetragonal | 1.63 | 0.0353 | -4.302 | 2.64 |
| P42/mnm (No. 136) | tetragonal | 1.60 | 0.0355 | -4.302 | 2.62 |
| P41212 (No. 92) | tetragonal | — | — | — | 2.70 |
| P42/mnm (No. 136) | tetragonal | — | — | — | 2.69 |
| P42/mnm (No. 136) | tetragonal | — | — | — | 2.62 |
| P42/mnm (No. 136) | tetragonal | — | — | — | 2.73 |
Applications
Where K3NiO2 is used.
Frequently Asked Questions
Common questions about K3NiO2, answered from cross-validated data.
What is K3NiO2?
K3NiO2 is a thermodynamically stable, semiconducting oxide material utilized in the study of oxygen-evolution catalysis.
What is K3NiO2 used for?
What is the band gap of K3NiO2?
Is K3NiO2 a metal, semiconductor, or insulator?
Is K3NiO2 thermodynamically stable?
What is the crystal structure of K3NiO2?
What is the density of K3NiO2?
How many polymorphs of K3NiO2 are known?
What elements does K3NiO2 contain?
Where does the data for K3NiO2 come from?
How It Compares
Within the oxide oxygen-evolution catalysts class.
Unlike the widely utilized transition metal oxides such as NiO or the layered lithium-based cathodes like LiNiO2 and LiCoO2, K3NiO2 features a unique stoichiometry that sets it apart from the more common perovskite-related structures like LaNiO3 or BiFeO3. While many of its class members are optimized for high-capacity battery performance, K3NiO2 is primarily distinguished by its thermodynamic stability and specific electronic character, offering a different structural approach to oxygen-evolution catalysis compared to the more conventional manganese or cobalt-based oxides.
Related Compounds
Other Oxide Oxygen-Evolution Catalysts in the database.
Data sources & attribution
- 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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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