K2NiO2
K2NiO2 is a stable, semiconducting oxide material utilized in the development of oxygen-evolution catalysts.
About K2NiO2
K2NiO2 is a thermodynamically stable oxide that functions as a semiconducting material. Its position on the convex hull suggests a robust structural integrity, making it a subject of interest for researchers investigating efficient catalytic pathways for oxygen evolution.
As a member of the oxide oxygen-evolution catalyst class, this compound leverages its electronic structure to facilitate electrochemical reactions. Its structural characteristics are well-documented across multiple databases, highlighting its significance in the study of transition metal oxides for energy-related applications.
Key Properties
Cross-validated computational properties for K2NiO2, 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 K2NiO2. 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 K2NiO2, 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. |
|---|---|---|---|---|---|
| — | — | 2.94 | 0.0000 | -1.311 | — |
| I4/mmm (No. 139) | tetragonal | 0.72 | 0.0000 | -1.340 | — |
| I4/mmm (No. 139) | tetragonal | 0.58 | 0.0000 | -4.889 | 2.86 |
| — | — | 2.21 | 0.0435 | -1.267 | — |
| — | — | 2.28 | 0.1892 | -1.122 | — |
| — | — | 0.87 | 0.4394 | -0.871 | — |
| I4/mmm (No. 139) | tetragonal | — | — | — | 2.85 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 2.80 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 2.70 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 2.76 |
Applications
Where K2NiO2 is used.
Frequently Asked Questions
Common questions about K2NiO2, answered from cross-validated data.
What is K2NiO2?
K2NiO2 is a stable, semiconducting oxide material utilized in the development of oxygen-evolution catalysts.
What is K2NiO2 used for?
What is the band gap of K2NiO2?
Is K2NiO2 a metal, semiconductor, or insulator?
Is K2NiO2 thermodynamically stable?
What is the crystal structure of K2NiO2?
How many polymorphs of K2NiO2 are known?
What elements does K2NiO2 contain?
Where does the data for K2NiO2 come from?
How It Compares
Within the oxide oxygen-evolution catalysts class.
Within the diverse family of nickel-based catalysts, K2NiO2 serves as a distinct alternative to more common oxides like NiO or layered materials such as LiNiO2 and La2NiO4. While many of its siblings are widely utilized in battery electrodes or complex perovskite catalytic systems, K2NiO2 offers a unique chemical environment that differentiates it from the more extensively studied cobalt and manganese-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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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