K3PO4
tripotassium phosphate · potassium phosphate tribasic, E340iii
Tripotassium phosphate is a stable, insulating salt commonly used as a food additive, buffering agent, and industrial chemical intermediate.
About tripotassium phosphate
Tripotassium phosphate is a highly stable, wide-band-gap insulating compound that exists as a robust crystalline solid. Its thermodynamic stability ensures it remains a reliable choice for chemical processes where consistent performance is required under various environmental conditions. The material is frequently utilized for its ability to regulate acidity and its effectiveness as a source of potassium and phosphorus. It plays a critical role in industrial applications ranging from food manufacturing to specialized chemical synthesis.
Key Properties
Cross-validated computational properties for tripotassium phosphate, 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 K3PO4. 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 K3PO4, 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 | 4.32 | 0.0000 | -2.360 | — |
| Pnma (No. 62) | orthorhombic | 4.00 | 0.0000 | -6.107 | 2.64 |
| — | — | 4.48 | 0.0007 | -2.437 | — |
| — | — | 4.57 | 0.0219 | -2.416 | — |
| — | — | 4.58 | 0.0316 | -2.406 | — |
| — | — | 4.37 | 0.0467 | -2.391 | — |
| — | — | 3.76 | 0.0583 | -2.379 | — |
| — | — | 4.05 | 0.0633 | -2.374 | — |
| — | — | 3.98 | 0.0683 | -2.369 | — |
| — | — | 2.67 | 0.0780 | -2.359 | — |
| — | — | 2.59 | 0.0900 | -2.348 | — |
| Pnma (No. 62) | orthorhombic | — | — | — | 2.64 |
Synthesis Routes
Literature-extracted synthesis procedures targeting K3PO4.
Applications
Where tripotassium phosphate is used.
Frequently Asked Questions
Common questions about tripotassium phosphate, answered from cross-validated data.
What is K3PO4?
Tripotassium phosphate is a stable, insulating salt commonly used as a food additive, buffering agent, and industrial chemical intermediate.
What is K3PO4 used for?
What is the band gap of K3PO4?
Is K3PO4 a metal, semiconductor, or insulator?
Is K3PO4 thermodynamically stable?
What is the crystal structure of K3PO4?
How many polymorphs of K3PO4 are known?
How is K3PO4 synthesized?
What elements does K3PO4 contain?
Where does the data for K3PO4 come from?
How It Compares
As a fundamental inorganic salt, tripotassium phosphate serves as a primary example of a stable, insulating phosphate compound, providing a benchmark for reactivity and solubility within its chemical family.
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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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