# Fe2U: enthalpy of formation

> Enthalpy of formation of Fe2U: 14 literature value(s) with sources, pages and quotes and DFT values (Materials Project / OQMD), from ORCHID.

HTML: https://data.orchid-project.org/compounds/Fe2U.html · Markdown: https://data.orchid-project.org/compounds/Fe2U.md

14 accepted literature formation-enthalpy value(s) (experimental 3, model 11); experimental median -14.01 kJ/mol-atom (n = 3); Materials Project -9.82 kJ/mol-atom (mp-aaaabfdq); OQMD -8.017 kJ/mol-atom (oqmd-19298).

Systems: [Fe–U](https://data.orchid-project.org/systems/FE-U.html)

## Literature values

Table: Enthalpy of formation of Fe2U reported in the literature (14)

| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---:|---|---:|---|---|---|---|---|---|
| -16.3 kJ/mol-atom ± 0.6 | Fe2U | 298.15 | experimental | High temperature solution calorimetry | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Labroche 2000_ | Table 3, p. 3, row 3; `ORC-SB3XW4RX7Z.0a16cb` |  |
| -14.01 kJ/mol-atom ± 1.8 | Fe2U | 298.15 | experimental | High temperature solution calorimetry | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Antony 1996_ [doi](https://doi.org/10.1016/0022-3115%2895%2900164-6) | Table 3, p. 3, row 2; `ORC-CN3ILEUCE2.2aaf0a` |  |
| -10.74 kJ/mol-atom ± 0.42 | Fe2U | 298.15 | experimental | Acid solution calorimetry | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Akhachinskiy 1962_ | Table 3, p. 3, row 1; `ORC-STB5INE33U.082a43` |  |
| -34.112 kJ/mol (basis unstated) | Fe2U | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003 | Table 7, p. 8, row 14; `ORC-IV62NRD2EY.0e33ca` |  |
| -30.08 kJ/mol (basis unstated) | Fe0.66U0.33 | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Kurata 2003_ | Table 7, p. 8, row 15; `ORC-RCRNRAUCL2.3e7f06` |  |
| -25.314 kJ/mol (basis unstated) | Fe2U | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Okamoto 1993_ [doi](https://doi.org/10.1007/bf02668229) | Table 7, p. 8, row 13; `ORC-HCLBHQ4LF6.4264b3` |  |
| -23.54 kJ/mol (basis unstated) ± 0.45 | Fe2U | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Kanno 1974_ | Table 7, p. 8, row 10; `ORC-CIRZQSRDRD.64fe30` |  |
| -20.6 kJ/mol (basis unstated) | Fe0.66U0.33 | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Campbell 1977_ [doi](https://doi.org/10.1007/bf02642864) | Table 7, p. 8, row 8; `ORC-X55MHENXWS.2cd47e` |  |
| -16.922 kJ/mol (basis unstated) | Fe2U | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003 | Table 7, p. 8, row 11; `ORC-CTC5MS5ZZV.6f0bb8` |  |
| -16.3 kJ/mol (basis unstated) ± 0.6 | Fe0.66U0.33 | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Labroche 2000_ | Table 7, p. 8, row 5; `ORC-VBXKMZ6DZF.444747` |  |
| -15.886 kJ/mol (basis unstated) | Fe0.66U0.33 | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003 | Table 7, p. 8, row 6; `ORC-YH6KSH5EMG.116370` |  |
| -15.025 kJ/mol (basis unstated) | Fe2U | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Gardie 1992_ [doi](https://doi.org/10.1016/0022-3115%2892%2990422-h) | Table 7, p. 8, row 12; `ORC-YVE44YNJYL.a555a7` |  |
| -14.01 kJ/mol (basis unstated) ± 1.8 | Fe0.66U0.33 | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Antony 1996_ [doi](https://doi.org/10.1016/0022-3115%2895%2900164-6) | Table 7, p. 8, row 7; `ORC-MK4JLSOV4H.152668` |  |
| -10.739 kJ/mol (basis unstated) ± 0.42 | Fe0.66U0.33 | 298.15 | model |  | [Fe–U](https://data.orchid-project.org/systems/FE-U.html) | [1] Chatain 2003; _cites Akhachinskiy 1962_ | Table 7, p. 8, row 9; `ORC-7LTITR3YTS.b419b9` |  |

### 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 Fe2U

| Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective |
|---:|---|---:|---:|---|---:|---:|---:|---:|
| -16.3 | kJ/mol-atom | 0.6 | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -14.01 | kJ/mol-atom | 1.8 | 0.005 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -10.74 | kJ/mol-atom | 0.42 | 0.005 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -34.112 | kJ/mol (basis unstated) |  | 5.000e-5 | 11.7 (model_calculated, calibrated) |  |  |  | 11.7 |
| -30.08 | kJ/mol (basis unstated) |  | 5.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -25.314 | kJ/mol (basis unstated) |  | 5.000e-5 | 11.7 (model_calculated, calibrated) |  |  |  | 11.7 |
| -23.54 | kJ/mol (basis unstated) | 0.45 | 5.000e-5 | 11.7 (model_calculated, calibrated) |  |  |  | 11.7 |
| -20.6 | kJ/mol (basis unstated) |  | 5.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -16.922 | kJ/mol (basis unstated) |  | 5.000e-5 | 11.7 (model_calculated, calibrated) |  |  |  | 11.7 |
| -16.3 | kJ/mol (basis unstated) | 0.6 | 5.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -15.886 | kJ/mol (basis unstated) |  | 5.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -15.025 | kJ/mol (basis unstated) |  | 5.000e-5 | 11.7 (model_calculated, calibrated) |  |  |  | 11.7 |
| -14.01 | kJ/mol (basis unstated) | 1.8 | 5.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -10.739 | kJ/mol (basis unstated) | 0.42 | 5.000e-4 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |

## 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 Fe2U

| Source | Entry | kJ/mol-atom | eV/atom | Space group | E above hull (kJ/mol-atom) | E above hull (eV/atom) | Theoretical |
|---|---|---:|---:|---|---:|---:|---|
| Materials Project | mp-aaaabfdq | -9.82 | -0.101774 | Fd-3m | 0 | 0 | no |
| OQMD | oqmd-19298 | -8.017 | -0.08309 | Fd-3m | 0.7002 | 0.0073 | 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. S. Chatain, C. Guéneau, D. Labroche, O. Dugne, J. Rogez, Thermodynamic assessment of the Fe-U binary system, JPE 24, 122-131 (2003). [doi:10.1361/105497103770330730](https://doi.org/10.1361/105497103770330730)

## 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/).