K3NiO2
This compound is a complex oxide containing potassium and nickel. It is primarily utilized in specialized chemical research to study the structural and electronic properties of nickel in unusual oxidation states.
Overview
Key Properties
Cross-validated computational properties for K3NiO2, 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.
0.22–1.63 eV
Range across DFT structures
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.
0.000 eV/atom
Best (lowest) across sources
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.
On hull (stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
8
3 databases, 4 space groups
Crystallography
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. |
|---|---|---|---|---|---|
| Cmcm (No. 63) | orthorhombic | 1.38 | 0.0000 | -5.145 | 3.46 |
| P21/m (No. 11) | monoclinic | 0.22 | 0.0000 | -8.737 | 3.62 |
| 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 |
| P42/mnm (No. 136) | Tetragonal | — | — | — | 2.62 |
| P42/mnm (No. 136) | Tetragonal | — | — | — | 2.73 |
| P42/mnm (No. 136) | Tetragonal | — | — | — | 2.69 |
| P42/mnm (No. 136) | — | — | — | — | — |
Uses
Applications
Where K3NiO2 is used.
Solid-state chemistry researchCatalysis studiesMaterials science investigations
Reference
Frequently Asked Questions
Common questions about K3NiO2, answered from cross-validated data.
What is K3NiO2?
This compound is a complex oxide containing potassium and nickel. It is primarily utilized in specialized chemical research to study the structural and electronic properties of nickel in unusual oxidation states.
More questions
What is K3NiO2 used for?
K3NiO2 is used in solid-state chemistry research, catalysis studies, and materials science investigations.
What is the band gap of K3NiO2?
K3NiO2 has a DFT-computed band gap of 0.22–1.63 eV across 8 reported structures.
Is K3NiO2 a metal, semiconductor, or insulator?
With a band gap up to 1.63 eV it is a semiconductor.
Is K3NiO2 thermodynamically stable?
Yes — K3NiO2 sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of K3NiO2?
The lowest-energy reported polymorph of K3NiO2 is orthorhombic symmetry, space group Cmcm (No. 63).
What is the density of K3NiO2?
The computed density of the ground-state structure of K3NiO2 is 3.46 g/cm³.
How many polymorphs of K3NiO2 are known?
8 structures of K3NiO2 are reported across 3 databases, spanning 4 distinct space groups.
What elements does K3NiO2 contain?
K3NiO2 contains K, Ni, and O (3 elements).
Where does the data for K3NiO2 come from?
K3NiO2 data is cross-referenced from materials_project, mpaloe, jarvis.
Explore
Related Compounds
Other Oxide Oxygen-Evolution Catalysts in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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