K2SO4
Potassium sulfate · Arcanite, Potash of sulfur
Potassium sulfate is a stable, insulating salt primarily used as a high-purity fertilizer and chemical feedstock.
About Potassium sulfate
Potassium sulfate is a robust inorganic salt that exists as a thermodynamically stable phase. Its electronic character as a wide-gap insulator makes it chemically inert under standard environmental conditions, ensuring it remains a reliable compound for industrial and agricultural applications.
Due to its high structural stability, this compound is frequently encountered in various crystalline forms. It serves as a vital chemical building block and is highly valued for its ability to provide essential nutrients without introducing chloride ions into sensitive soil environments.
Key Properties
Cross-validated computational properties for Potassium sulfate, 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 K2SO4. 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 K2SO4, 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. |
|---|---|---|---|---|---|
| Pnma (No. 62) | orthorhombic | 5.86 | 0.0000 | -2.007 | — |
| — | — | 5.76 | 0.0000 | -2.159 | — |
| Pnma (No. 62) | orthorhombic | 5.22 | 0.0000 | -6.013 | 2.71 |
| C2/c (No. 15) | monoclinic | 5.04 | 0.0118 | -6.002 | 2.40 |
| Cmcm (No. 63) | orthorhombic | 5.21 | 0.0179 | -1.989 | — |
| Cmcm (No. 63) | orthorhombic | 4.90 | 0.0251 | -5.988 | 2.53 |
| Cmcm (No. 63) | orthorhombic | 5.46 | 0.0261 | -1.981 | — |
| — | — | 5.57 | 0.0347 | -2.124 | — |
| — | — | 2.86 | 0.7386 | -1.420 | — |
| — | — | 2.15 | 0.7569 | -1.402 | — |
| P-3m1 (No. 164) | trigonal | 0.00 | 1.7504 | -0.256 | — |
| P-3m1 (No. 164) | trigonal | 0.00 | 1.8124 | -4.201 | 2.36 |
Applications
Where Potassium sulfate is used.
Frequently Asked Questions
Common questions about Potassium sulfate, answered from cross-validated data.
What is K2SO4?
Potassium sulfate is a stable, insulating salt primarily used as a high-purity fertilizer and chemical feedstock.
What is K2SO4 used for?
What is the band gap of K2SO4?
Is K2SO4 a metal, semiconductor, or insulator?
Is K2SO4 thermodynamically stable?
What is the crystal structure of K2SO4?
How many polymorphs of K2SO4 are known?
What elements does K2SO4 contain?
Where does the data for K2SO4 come from?
How It Compares
As a prominent and highly stable inorganic salt, this compound serves as a benchmark for potassium-based minerals, maintaining a consistent structural integrity that defines the standard for its chemical class.
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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