Rb2NiO2
Rb2NiO2 is a stable, semiconducting oxide compound utilized in the study of oxygen-evolution catalysis.
About Rb2NiO2
Rb2NiO2 is a semiconducting oxide that holds a significant position within the field of oxygen-evolution catalysts. As a thermodynamically stable phase residing on the convex hull, it represents a well-defined structural arrangement of rubidium, nickel, and oxygen atoms.
Its electronic character makes it a subject of interest for researchers investigating charge transfer and catalytic activity in energy storage and conversion systems. The compound is characterized by a robust structural framework, supported by multiple reported configurations across materials databases.
Key Properties
Cross-validated computational properties for Rb2NiO2, 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 Rb2NiO2. 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 Rb2NiO2, 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. |
|---|---|---|---|---|---|
| — | — | 2.82 | 0.0000 | -1.267 | — |
| I4/mmm (No. 139) | tetragonal | 2.81 | 0.0000 | -4.793 | 3.84 |
| I4/mmm (No. 139) | tetragonal | 1.00 | 0.0000 | -1.308 | — |
| — | — | 1.19 | 0.2270 | -1.040 | — |
| I4/mmm (No. 139) | tetragonal | — | — | — | 3.81 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 3.69 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 3.75 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 3.86 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 3.84 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 3.85 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 3.85 |
Applications
Where Rb2NiO2 is used.
Frequently Asked Questions
Common questions about Rb2NiO2, answered from cross-validated data.
What is Rb2NiO2?
Rb2NiO2 is a stable, semiconducting oxide compound utilized in the study of oxygen-evolution catalysis.
What is Rb2NiO2 used for?
What is the band gap of Rb2NiO2?
Is Rb2NiO2 a metal, semiconductor, or insulator?
Is Rb2NiO2 thermodynamically stable?
What is the crystal structure of Rb2NiO2?
What is the density of Rb2NiO2?
How many polymorphs of Rb2NiO2 are known?
What elements does Rb2NiO2 contain?
Where does the data for Rb2NiO2 come from?
How It Compares
Within the oxide oxygen-evolution catalysts class.
Unlike the more common transition metal oxides like NiO or the layered cathode materials such as LiNiO2 and LiCoO2, Rb2NiO2 features a distinct alkali-rich stoichiometry that influences its catalytic behavior and structural stability. While materials like LaNiO3 or La2NiO4 are frequently studied for their complex perovskite-related lattices, Rb2NiO2 offers a unique chemical environment that provides a different perspective on nickel-based oxygen evolution pathways.
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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (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)
- 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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