KCO2
KCO2 is a semiconducting ternary compound of potassium, carbon, and oxygen that is considered a promising candidate for laboratory synthesis.
About KCO2
KCO2 is an intriguing inorganic compound composed of potassium, carbon, and oxygen. As a semiconducting material, it occupies a unique niche in solid-state chemistry, offering distinct electronic properties that differentiate it from common insulating oxides or metallic conductors. Its structural complexity is evidenced by a significant number of reported configurations across major databases.
Because it is identified as a near-hull material, KCO2 is considered a prime candidate for experimental synthesis. Its stability profile suggests that while it may not be the most common phase, it remains a viable target for researchers investigating novel ternary oxides and potential functional materials for electronic or catalytic applications.
Key Properties
Cross-validated computational properties for KCO2, 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 KCO2. 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 KCO2, 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. |
|---|---|---|---|---|---|
| Pbam (No. 55) | orthorhombic | 2.73 | 0.0029 | -1.677 | — |
| — | — | 2.77 | 0.0083 | -1.766 | — |
| Pbam (No. 55) | orthorhombic | 2.75 | 0.0136 | -6.965 | 2.44 |
| Cm (No. 8) | monoclinic | — | — | — | 2.26 |
| Cm (No. 8) | monoclinic | — | — | — | 1.80 |
| Pmn21 (No. 31) | orthorhombic | — | — | — | 3.83 |
| Pbam (No. 55) | orthorhombic | — | — | — | 2.39 |
| Cm (No. 8) | monoclinic | — | — | — | 1.54 |
| Pbam (No. 55) | orthorhombic | — | — | — | 2.40 |
| Pbam (No. 55) | orthorhombic | — | — | — | 2.31 |
| Pbam (No. 55) | orthorhombic | — | — | — | 2.29 |
| Pmmn (No. 59) | orthorhombic | — | — | — | 1.94 |
Applications
Where KCO2 is used.
Frequently Asked Questions
Common questions about KCO2, answered from cross-validated data.
What is KCO2?
KCO2 is a semiconducting ternary compound of potassium, carbon, and oxygen that is considered a promising candidate for laboratory synthesis.
What is KCO2 used for?
What is the band gap of KCO2?
Is KCO2 a metal, semiconductor, or insulator?
Is KCO2 thermodynamically stable?
What is the crystal structure of KCO2?
How many polymorphs of KCO2 are known?
What elements does KCO2 contain?
Where does the data for KCO2 come from?
How It Compares
As a standalone entry in this specific chemical space, KCO2 serves as a foundational reference point for understanding the behavior of potassium-based carbon oxides. Without direct structural siblings in this class, it represents an isolated yet significant case study for how alkali metals influence the electronic environment of carbon-oxygen frameworks.
Data sources & attribution
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- 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)
- 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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