P2O5
phosphorus pentoxide · phosphoric anhydride, diphosphorus pentoxide
Phosphorus pentoxide is a highly reactive, stable white solid primarily used as a powerful drying agent and a versatile chemical intermediate in industrial manufacturing.

About phosphorus pentoxide
Phosphorus pentoxide is a thermodynamically stable oxide that serves as the acid anhydride of phosphoric acid. Its insulating electronic character and high reactivity toward water make it a critical component in chemical processing and synthesis.
Due to its extensive structural diversity, this compound is frequently studied for its varied polymorphic forms. It is widely utilized in industrial settings as a potent desiccant and a key reagent for the production of phosphate esters and other phosphorus-based derivatives.
Key Properties
Cross-validated computational properties for phosphorus pentoxide, 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.
Reported Structures
Lowest-energy structures reported for P2O5, 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 | 4.84 | 0.0000 | -7.531 | 2.91 |
| Fdd2 (No. 43) | orthorhombic | 5.20 | 0.0108 | -7.520 | 2.72 |
| P1 (No. 1) | triclinic | 4.95 | 0.0468 | -7.484 | 2.51 |
| R3c (No. 161) | trigonal | 5.54 | 0.0509 | -7.480 | 2.33 |
| P1 (No. 1) | triclinic | 1.76 | 0.5669 | -6.964 | 1.99 |
| Pmmm (No. 47) | orthorhombic | 0.00 | 0.6877 | -6.843 | 3.94 |
| P1 (No. 1) | triclinic | 0.01 | 0.7254 | -6.805 | 1.89 |
| P1 (No. 1) | triclinic | 1.12 | 0.7435 | -6.787 | 1.65 |
| P1 (No. 1) | triclinic | 0.02 | 0.7716 | -6.759 | 2.04 |
| P1 (No. 1) | triclinic | 0.31 | 0.8139 | -6.717 | 1.89 |
| Cc (No. 9) | monoclinic | 0.07 | 1.5718 | -5.959 | 0.82 |
| R3c (No. 161) | trigonal | 0.22 | 1.8181 | -5.713 | 1.88 |
Synthesis Routes
Literature-extracted synthesis procedures targeting P2O5.
Applications
Where phosphorus pentoxide is used.
Frequently Asked Questions
Common questions about phosphorus pentoxide, answered from cross-validated data.
What is P2O5?
Phosphorus pentoxide is a highly reactive, stable white solid primarily used as a powerful drying agent and a versatile chemical intermediate in industrial manufacturing.
What is P2O5 used for?
What is the band gap of P2O5?
Is P2O5 a metal, semiconductor, or insulator?
Is P2O5 thermodynamically stable?
What is the crystal structure of P2O5?
What is the density of P2O5?
How many polymorphs of P2O5 are known?
How is P2O5 synthesized?
What elements does P2O5 contain?
Where does the data for P2O5 come from?
How It Compares
As a fundamental oxide in phosphorus chemistry, this compound serves as a primary reference point for dehydration and phosphorylation reactions, defining the standard behavior for high-stability phosphorus-oxygen systems.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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