K2CO3
potassium carbonate · potash, pearl ash, salt of tartar
Potassium carbonate is a stable, insulating inorganic salt widely utilized as a versatile chemical reagent and industrial base.
About potassium carbonate
Potassium carbonate is a thermodynamically stable inorganic compound that exhibits wide-band-gap insulating behavior. Its robust structural profile, supported by numerous experimental reports, makes it a reliable and essential reagent in industrial chemistry.
This compound serves as a critical precursor for various potassium-based chemicals and is frequently employed as a mild alkaline agent. Its stability under standard conditions ensures its utility across a broad spectrum of manufacturing and laboratory applications.
Key Properties
Cross-validated computational properties for potassium carbonate, 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 K2CO3. 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 K2CO3, 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. |
|---|---|---|---|---|---|
| P21/c (No. 14) | monoclinic | 4.27 | 0.0000 | -1.910 | — |
| — | — | 4.08 | 0.0000 | -1.981 | — |
| P21/c (No. 14) | monoclinic | 3.65 | 0.0000 | -6.499 | 2.47 |
| — | — | 3.82 | 0.0002 | -1.981 | — |
| C2/c (No. 15) | monoclinic | 4.27 | 0.0013 | -1.909 | — |
| — | — | 4.36 | 0.0022 | -1.979 | — |
| C2/c (No. 15) | monoclinic | 3.63 | 0.0023 | -6.497 | 2.48 |
| — | — | 3.66 | 0.0082 | -1.973 | — |
| P63/mmc (No. 194) | hexagonal | 3.29 | 0.0152 | -6.484 | 2.36 |
| P63/mmc (No. 194) | hexagonal | 3.73 | 0.0179 | -1.892 | — |
| — | — | 0.95 | 0.0655 | -1.916 | — |
| — | — | 3.94 | 0.0785 | -1.903 | — |
Applications
Where potassium carbonate is used.
Frequently Asked Questions
Common questions about potassium carbonate, answered from cross-validated data.
What is K2CO3?
Potassium carbonate is a stable, insulating inorganic salt widely utilized as a versatile chemical reagent and industrial base.
What is K2CO3 used for?
What is the band gap of K2CO3?
Is K2CO3 a metal, semiconductor, or insulator?
Is K2CO3 thermodynamically stable?
What is the crystal structure of K2CO3?
How many polymorphs of K2CO3 are known?
What elements does K2CO3 contain?
Where does the data for K2CO3 come from?
How It Compares
As a fundamental inorganic salt, this compound functions as a cornerstone of industrial chemistry, providing a stable and highly soluble source of potassium that is indispensable for large-scale chemical synthesis and glass production.
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)
- 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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