Ca3P2
calcium phosphide · tricalcium diphosphide
Calcium phosphide is a reactive, semiconducting inorganic compound primarily utilized for its ability to generate phosphine gas upon hydrolysis.
About calcium phosphide
Calcium phosphide is a binary inorganic compound composed of calcium and phosphorus. It functions as a semiconductor and is recognized for its high reactivity, particularly when exposed to moisture, which leads to the release of phosphine gas.
Due to its tendency to exist above the thermodynamic hull, it is considered a metastable material that requires careful handling. Its primary utility stems from its chemical reactivity, making it a specialized reagent in industrial and agricultural settings.
Key Properties
Cross-validated computational properties for calcium phosphide, aggregated across 5 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 Ca3P2. 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 Ca3P2, 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. |
|---|---|---|---|---|---|
| — | — | 1.54 | 0.0000 | -1.223 | — |
| — | — | 0.58 | 0.0993 | -1.123 | — |
| Pm-3m (No. 221) | cubic | 0.51 | 0.1388 | -0.848 | — |
| Pm-3m (No. 221) | cubic | 0.35 | 0.1460 | -8.941 | 2.02 |
| P-1 (No. 2) | triclinic | — | — | — | 1.63 |
| R-3m (No. 166) | trigonal | — | — | — | 2.09 |
| P-1 (No. 2) | triclinic | — | — | — | 2.13 |
| R-3m (No. 166) | trigonal | — | — | — | 2.70 |
| R-3m (No. 166) | trigonal | — | — | -4.308 | 1.98 |
| Pm-3m (No. 221) | cubic | — | — | — | 2.03 |
| P-1 (No. 2) | triclinic | — | — | — | 1.31 |
| R-3m (No. 166) | trigonal | — | — | — | 2.00 |
Applications
Where calcium phosphide is used.
Frequently Asked Questions
Common questions about calcium phosphide, answered from cross-validated data.
What is Ca3P2?
Calcium phosphide is a reactive, semiconducting inorganic compound primarily utilized for its ability to generate phosphine gas upon hydrolysis.
What is Ca3P2 used for?
What is the band gap of Ca3P2?
Is Ca3P2 a metal, semiconductor, or insulator?
Is Ca3P2 thermodynamically stable?
What is the crystal structure of Ca3P2?
How many polymorphs of Ca3P2 are known?
What elements does Ca3P2 contain?
Where does the data for Ca3P2 come from?
How It Compares
As a binary phosphide, calcium phosphide occupies a distinct niche in materials science where its semiconducting nature is balanced against its inherent thermodynamic instability, setting it apart from more robust, inert ceramic phases.
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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- aflow — Data from AFLOW (aflow.org). Cite: Curtarolo et al., Comp. Mater. Sci. 58, 218 (2012). (CC-BY-4.0)
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