# Zn3P2: enthalpy of formation

> Enthalpy of formation of Zn3P2: 13 literature value(s) with sources, pages and quotes and DFT values (Materials Project / OQMD), from ORCHID.

HTML: https://data.orchid-project.org/compounds/Zn3P2.html · Markdown: https://data.orchid-project.org/compounds/Zn3P2.md

13 accepted literature formation-enthalpy value(s) (experimental 6, model 5, unspecified 2); experimental median -39.65 kJ/mol-atom (n = 6); Materials Project -18.169 kJ/mol-atom (mp-aaaaadbr); OQMD -27.768 kJ/mol-atom (oqmd-14030).

Systems: [P–Zn](https://data.orchid-project.org/systems/P-ZN.html)

## Literature values

Table: Enthalpy of formation of Zn3P2 reported in the literature (13)

| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---:|---|---:|---|---|---|---|---|---|
| -46.06 kJ/mol-atom ± 6300 | Zn3P2 | 298.15 | experimental |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [1] Liu 2016; _cites Karvelis 1959_ | Table 4, p. 6, row 4; `ORC-6G5UCN3PYT` |  |
| -46.06 kJ/mol-atom ± 1.26 | Zn3P2 | 298.15 | experimental |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [2] Tu 2009; _cites Karvelis 1959_ | Table 3, p. 4, row 8; `ORC-MWD4MEQCQL` |  |
| -44.66 kJ/mol-atom ± 0.3 | Zn3P2 | 298.15 | experimental |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [2] Tu 2009; _cites Karvelis 1959_ | Table 3, p. 4, row 9; `ORC-NFWOS5535K` |  |
| -34.64 kJ/mol-atom ± 2.08 | Zn3P2 | 298.15 | experimental |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [2] Tu 2009; _cites Sirota 1975_ | Table 3, p. 4, row 6; `ORC-LWXR2TG7QI.334c1f` |  |
| -33.06 kJ/mol-atom ± 4.18 | Zn3P2 | 298.15 | experimental |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [2] Tu 2009; _cites Schoonmaker 1967_ [doi](https://doi.org/10.1021/j100867a043) | Table 3, p. 4, row 7; `ORC-3W2FGGUKTH` |  |
| -33.06 kJ/mol-atom ± 20900 | Zn3P2 | 298.15 | experimental |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [1] Liu 2016; _cites Schoonmaker 1967_ [doi](https://doi.org/10.1021/j100867a043) | Table 4, p. 6, row 3; `ORC-CIWTGTH2YD` |  |
| -181.78 kJ/mol (basis unstated) | Zn3P2 | 298.15 | model |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [3] Ghasemi 2019; _cites Tu 2009_ [doi](https://doi.org/10.1016/j.calphad.2009.10.003) | Table 2, p. 3, row 2; `ORC-5QGOL6UF5I.bc2a85` |  |
| -151.839 kJ/mol (basis unstated) | Zn3P2 | 298.15 | model |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [3] Ghasemi 2019; _cites Liu 2016_ [doi](https://doi.org/10.1016/j.surfcoat.2016.01.016) | Table 2, p. 3, row 1; `ORC-YVXEYCTMZN.2d2913` |  |
| -36.356 kJ/mol-atom | Zn3P2 | 298.15 | model |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [2] Tu 2009 | Table 3, p. 4, row 10; `ORC-4NHSU4IPIC.488e37` |  |
| -36.356 kJ/mol-atom | Zn3P2 | 298.15 | model |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [1] Liu 2016; _cites Tu 2009_ [doi](https://doi.org/10.1016/j.calphad.2009.10.003) | Table 4, p. 6, row 6; `ORC-V67L7I2OM7.4baa15` |  |
| -30.3678 kJ/mol-atom | Zn3P2 | 298.15 | model |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [1] Liu 2016 | Table 4, p. 6, row 1; `ORC-24MG5TAEG6.73186d` |  |
| -44.66 kJ/mol-atom ± 1500 | Zn3P2 | 298.15 | unspecified |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [1] Liu 2016; _cites Karvelis 1959_ | Table 4, p. 6, row 5; `ORC-H6HJEGQSCS` |  |
| -34.64 kJ/mol-atom ± 10400 | Zn3P2 | 298.15 | unspecified |  | [P–Zn](https://data.orchid-project.org/systems/P-ZN.html) | [1] Liu 2016; _cites Sirota 2016_ | Table 4, p. 6, row 2; `ORC-7KX4AFY722.74dbf0` |  |

### Uncertainty budget

Components kept separate, in the value's unit (literature [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md), [UNCERTAINTY_CALIBRATION.md](https://data.orchid-project.org/literature/UNCERTAINTY_CALIBRATION.md)): effective = max(sqrt(max(printed, reading, method)^2 + composition^2 + conversion^2), scatter). The method floor is the robust between-study scatter of the method class in ORCHID (calibrated) or a documented prior; printed values and printed uncertainties are unchanged.

Table: Uncertainty budget of the literature values of Zn3P2

| Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective |
|---:|---|---:|---:|---|---:|---:|---:|---:|
| -46.06 | kJ/mol-atom | 6300 | 1.000e-4 | 3.5 (unknown, calibrated) |  |  |  | 6300 |
| -46.06 | kJ/mol-atom | 1.26 | 1.000e-4 | 3.5 (unknown, calibrated) |  |  |  | 3.5 |
| -44.66 | kJ/mol-atom | 0.3 | 1.000e-4 | 3.5 (unknown, calibrated) |  |  |  | 3.5 |
| -34.64 | kJ/mol-atom | 2.08 | 1.000e-4 | 3.5 (unknown, calibrated) |  |  |  | 3.5 |
| -33.06 | kJ/mol-atom | 4.18 | 1.000e-4 | 3.5 (unknown, calibrated) |  |  |  | 4.18 |
| -33.06 | kJ/mol-atom | 20900 | 1.000e-4 | 3.5 (unknown, calibrated) |  |  |  | 20900 |
| -181.78 | kJ/mol (basis unstated) |  | 5.000e-5 | 19.5 (model_calculated, calibrated) |  |  |  | 19.5 |
| -151.839 | kJ/mol (basis unstated) |  | 5.000e-5 | 19.5 (model_calculated, calibrated) |  |  |  | 19.5 |
| -36.356 | kJ/mol-atom |  | 1.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -36.356 | kJ/mol-atom |  | 1.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -30.3678 | kJ/mol-atom |  | 1.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -44.66 | kJ/mol-atom | 1500 | 1.000e-4 | 3.5 (unknown, calibrated) |  |  |  | 1500 |
| -34.64 | kJ/mol-atom | 10400 | 1.000e-4 | 3.5 (unknown, calibrated) |  |  |  | 10400 |

## DFT formation energies

Lowest-energy entries at this composition. Materials Project and OQMD use different energy references and are never averaged. 1 eV/atom = 96.485 kJ/mol-atom.

Table: DFT formation energy of Zn3P2

| Source | Entry | kJ/mol-atom | eV/atom | Space group | E above hull (kJ/mol-atom) | E above hull (eV/atom) | Theoretical |
|---|---|---:|---:|---|---:|---:|---|
| Materials Project | mp-aaaaadbr | -18.169 | -0.188314 | P4_2/nmc | 0 | 0 | no |
| OQMD | oqmd-14030 | -27.768 | -0.287798 | P42/nmc | 0 | 0 | no |

DFT sources: A. Jain et al., Commentary: The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002. [doi:10.1063/1.4812323](https://doi.org/10.1063/1.4812323) (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501-1509; S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010. [doi:10.1007/s11837-013-0755-4](https://doi.org/10.1007/s11837-013-0755-4) (CC BY 4.0); 

## Sources

1. Ya Liu, Bin Zhou, Wei Lv, Changjun Wu, Xuping Su, Jianhua Wang, Experimental investigation and thermodynamic assessment of the Zn–Si–P system, Surface and Coatings Technology 306, 370-377 (2016). [doi:10.1016/j.surfcoat.2016.01.016](https://doi.org/10.1016/j.surfcoat.2016.01.016)
2. Hao Tu, Fucheng Yin, Xuping Su, Ya Liu, Xinming Wang, Experimental investigation and thermodynamic modeling of the Al–P–Zn ternary system, Calphad 33, 755-760 (2009). [doi:10.1016/j.calphad.2009.10.003](https://doi.org/10.1016/j.calphad.2009.10.003)
3. Masoomeh Ghasemi, E. Stutz, S. Escobar Steinvall, M. Zamani, A. Fontcuberta i Morral, Thermodynamic re-assessment of the Zn–P binary system, Materialia 6, 100301 (2019). [doi:10.1016/j.mtla.2019.100301](https://doi.org/10.1016/j.mtla.2019.100301)

## Please cite

- R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735569
- R. Arróyave, J. Saal, D. Shin, ORCHID-Parity: DFT-vs-experiment formation-enthalpy benchmark (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735943
- R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23736065

Also cite the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0); G. Kim, S. V. Meschel, P. Nash, W. Chen, Experimental formation enthalpies for intermetallic phases and other inorganic compounds, Scientific Data 4 (2017) 170162, https://doi.org/10.1038/sdata.2017.162; B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file.

Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes.

```bibtex
@misc{orchid_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_dft_benchmark_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Parity: DFT-vs-experiment formation-enthalpy benchmark}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735943},
  url       = {https://doi.org/10.5281/zenodo.23735943},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_data_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID data: umbrella record of the ORCHID datasets}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736065},
  url       = {https://doi.org/10.5281/zenodo.23736065},
  note      = {Version 1, machine-extracted}
}
```

---

Derived data CC BY 4.0 ([licence](https://creativecommons.org/licenses/by/4.0/)): cite ORCHID ([CITATION.cff](https://data.orchid-project.org/CITATION.cff)) and the original sources. Quotes are short excerpts kept so that each value can be checked; they remain under the publishers' copyright and are not relicensed. Source papers, page images and full text are not redistributed. Field reference: [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt). Found an error? The report link of a value (Markdown: its id, ORC-..., in the Location column) opens a pre-filled GitHub issue, https://github.com/orchid-calphad/orchid-data/issues/new?template=report-value-error.yml&record_id=\<id>, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).