Na2PHO4
disodium phosphate · disodium hydrogen phosphate, DSP
Disodium phosphate is a stable, insulating salt commonly used as a buffering agent and food additive.
About disodium phosphate
Na2PHO4 is a thermodynamically stable inorganic salt that functions as a wide-gap insulator. Its robust structural profile, supported by multiple documented configurations, makes it a reliable component in various industrial and laboratory chemical processes.
Because of its ability to maintain stable pH levels, this compound is essential in applications requiring precise chemical buffering. Its insulating electronic character and stability ensure consistent performance across a range of aqueous and solid-state environments.
Key Properties
Cross-validated computational properties for disodium 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 Na2PHO4. 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 Na2PHO4, 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. |
|---|---|---|---|---|---|
| — | — | 5.25 | 0.0000 | -2.285 | — |
| P21/c (No. 14) | monoclinic | 5.14 | 0.0000 | -2.115 | — |
| P21/c (No. 14) | monoclinic | 4.75 | 0.0000 | -6.268 | 2.49 |
| P21 (No. 4) | monoclinic | 4.67 | 0.0042 | -6.264 | 2.48 |
| P21/m (No. 11) | monoclinic | — | — | — | 2.58 |
| P21/c (No. 14) | monoclinic | — | — | — | 2.54 |
| P21 (No. 4) | monoclinic | — | — | — | 2.48 |
| P21 (No. 4) | monoclinic | — | — | — | 2.61 |
| P21/c (No. 14) | monoclinic | — | — | — | 2.49 |
| P21 (No. 4) | monoclinic | — | — | — | 2.53 |
| P21/c (No. 14) | monoclinic | — | — | — | 2.62 |
Applications
Where disodium phosphate is used.
Frequently Asked Questions
Common questions about disodium phosphate, answered from cross-validated data.
What is Na2PHO4?
Disodium phosphate is a stable, insulating salt commonly used as a buffering agent and food additive.
What is Na2PHO4 used for?
What is the band gap of Na2PHO4?
Is Na2PHO4 a metal, semiconductor, or insulator?
Is Na2PHO4 thermodynamically stable?
What is the crystal structure of Na2PHO4?
What is the density of Na2PHO4?
How many polymorphs of Na2PHO4 are known?
What elements does Na2PHO4 contain?
Where does the data for Na2PHO4 come from?
How It Compares
As a versatile phosphate salt, this compound serves as a fundamental building block in chemical manufacturing, providing a stable and predictable foundation for buffering and processing applications without the complexity often found in more exotic inorganic materials.
Data sources & attribution
- 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)
- 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)
- 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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