# Al–Np–Pu–U system

> Al–Np–Pu–U system: 36 accepted literature values (heat capacity / entropy / enthalpy 24, formation 12) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/AL-NP-PU-U.html · Markdown: https://data.orchid-project.org/systems/AL-NP-PU-U.md

36 accepted literature values from 1 paper(s) (DFT 36); 0 calculated phase diagram(s).

Data: [JSON](https://data.orchid-project.org/literature/systems/AL-NP-PU-U.json) · [CSV](https://data.orchid-project.org/systems/AL-NP-PU-U.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#AL-NP-PU-U) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/AL-NP-PU-U.html) · [Markdown](https://data.orchid-project.org/systems/AL-NP-PU-U.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| DFT | 36 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| formation | 12 |
| heat capacity / entropy / enthalpy | 24 |

## Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from [dft_parity.json](https://data.orchid-project.org/literature/dft_parity.json).

Table: Enthalpies of formation, Al–Np–Pu–U system (6)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| NpA12 |  | -110.2 kJ/mol (basis unstated) |  | DFT |  |  | [1] Sedmidubský 2010 | Table 2, p. 3, row 2; `ORC-AZTCA3FNXM.26285e` |  |
| NpA13 |  | -122.9 kJ/mol (basis unstated) |  | DFT |  |  | [1] Sedmidubský 2010 | Table 2, p. 3, row 5; `ORC-MQPU74X72L.22844f` |  |
| NpA14 |  | -105.6 kJ/mol (basis unstated) |  | DFT |  |  | [1] Sedmidubský 2010 | Table 2, p. 3, row 10; `ORC-UCH5KWJ6UG.e779f0` |  |
| PuA12 |  | -159.2 kJ/mol (basis unstated) |  | DFT |  |  | [1] Sedmidubský 2010 | Table 2, p. 3, row 3; `ORC-EXMKTYQAEE.362e5e` |  |
| UA12 |  | -86.1 kJ/mol (basis unstated) |  | DFT |  |  | [1] Sedmidubský 2010 | Table 2, p. 3, row 1; `ORC-MZ2XRS7TQV.a9c091` |  |
| UA13 |  | -87 kJ/mol (basis unstated) |  | DFT |  |  | [1] Sedmidubský 2010 | Table 2, p. 3, row 4; `ORC-OZIZ5AB43L.6c7acf` |  |

## Other properties

### Formation (6)

Table: Formation, Al–Np–Pu–U system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Entropy of formation; _printed: ΔfS°298_ | -2.3 J/mol (basis unstated)/K | 298.15 | NpA12; _alloy: Np 0.333333, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 2; `ORC-AZTCA3FNXM.2f03c4` |  |
| Entropy of formation; _printed: ΔfS°298_ | -12.1 J/mol (basis unstated)/K | 298.15 | NpA13; _alloy: Np 0.25, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 5; `ORC-MQPU74X72L.f6a218` |  |
| Entropy of formation; _printed: ΔfS°298_ | -8.1 J/mol (basis unstated)/K | 298.15 | NpA14; _alloy: Np 0.2, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 10; `ORC-UCH5KWJ6UG.3dc381` |  |
| Entropy of formation; _printed: ΔfS°298_ | -1.4 J/mol (basis unstated)/K | 298.15 | PuA12; _alloy: Np 0, Pu 0.333333, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 3; `ORC-EXMKTYQAEE.851583` |  |
| Entropy of formation; _printed: ΔfS°298_ | -1.1 J/mol (basis unstated)/K | 298.15 | UA12; _alloy: Np 0, Pu 0, U 0.333333_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 1; `ORC-MZ2XRS7TQV.01d71c` |  |
| Entropy of formation; _printed: ΔfS°298_ | -13.1 J/mol (basis unstated)/K | 298.15 | UA13; _alloy: Np 0, Pu 0, U 0.25_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 4; `ORC-OZIZ5AB43L.c79eed` |  |

### Heat capacity / entropy / enthalpy (24)

Table: Heat capacity / entropy / enthalpy, Al–Np–Pu–U system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| heat content contribution; _printed: H°298 − H°0 (el.)_ | 0.78 kJ mol−1 | 298.15 | NpA12; _alloy: Np 0.333333, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 2; `ORC-AZTCA3FNXM.ab2a52` |  |
| heat content contribution; _printed: H°298 − H°0 (ph.)_ | 24.2 kJ mol−1 | 298.15 | NpA12; _alloy: Np 0.333333, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 2; `ORC-AZTCA3FNXM.db54de` |  |
| heat content contribution; _printed: H°298 − H°0 (el.)_ | 0.39 kJ mol−1 | 298.15 | NpA13; _alloy: Np 0.25, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 5; `ORC-MQPU74X72L.38b589` |  |
| heat content contribution; _printed: H°298 − H°0 (ph.)_ | 32.1 kJ mol−1 | 298.15 | NpA13; _alloy: Np 0.25, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 5; `ORC-MQPU74X72L.4d99d5` |  |
| heat content contribution; _printed: H°298 − H°0 (ph.)_ | 40.5 kJ mol−1 | 298.15 | NpA14; _alloy: Np 0.2, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 10; `ORC-UCH5KWJ6UG.d25593` |  |
| heat content contribution; _printed: H°298 − H°0 (el.)_ | 0.51 kJ mol−1 | 298.15 | NpA14; _alloy: Np 0.2, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 10; `ORC-UCH5KWJ6UG.f1b11c` |  |
| heat content contribution; _printed: H°298 − H°0 (ph.)_ | 24.1 kJ mol−1 | 298.15 | PuA12; _alloy: Np 0, Pu 0.333333, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 3; `ORC-EXMKTYQAEE.282b7d` |  |
| heat content contribution; _printed: H°298 − H°0 (el.)_ | 0.64 kJ mol−1 | 298.15 | PuA12; _alloy: Np 0, Pu 0.333333, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 3; `ORC-EXMKTYQAEE.9c428a` |  |
| heat content contribution; _printed: H°298 − H°0 (el.)_ | 0.67 kJ mol−1 | 298.15 | UA12; _alloy: Np 0, Pu 0, U 0.333333_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 1; `ORC-MZ2XRS7TQV.18800e` |  |
| heat content contribution; _printed: H°298 − H°0 (ph.)_ | 24.2 kJ mol−1 | 298.15 | UA12; _alloy: Np 0, Pu 0, U 0.333333_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 1; `ORC-MZ2XRS7TQV.546bba` |  |
| heat content contribution; _printed: H°298 − H°0 (el.)_ | 0.65 kJ mol−1 | 298.15 | UA13; _alloy: Np 0, Pu 0, U 0.25_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 4; `ORC-OZIZ5AB43L.6f205a` |  |
| heat content contribution; _printed: H°298 − H°0 (ph.)_ | 32.3 kJ mol−1 | 298.15 | UA13; _alloy: Np 0, Pu 0, U 0.25_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 4; `ORC-OZIZ5AB43L.c9696b` |  |
| sm contribution; _printed: S°298 (ph.)_ | 99.5 J/mol (basis unstated)/K | 298.15 | NpA12; _alloy: Np 0.333333, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 2; `ORC-AZTCA3FNXM.a1f71c` |  |
| sm contribution; _printed: S°298 (el.)_ | 5.2 J/mol (basis unstated)/K | 298.15 | NpA12; _alloy: Np 0.333333, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 2; `ORC-AZTCA3FNXM.b5747a` |  |
| sm contribution; _printed: S°298 (el.)_ | 2.6 J/mol (basis unstated)/K | 298.15 | NpA13; _alloy: Np 0.25, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 5; `ORC-MQPU74X72L.a8bc29` |  |
| sm contribution; _printed: S°298 (ph.)_ | 120.6 J/mol (basis unstated)/K | 298.15 | NpA13; _alloy: Np 0.25, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 5; `ORC-MQPU74X72L.fedd5d` |  |
| sm contribution; _printed: S°298 (ph.)_ | 152.1 J/mol (basis unstated)/K | 298.15 | NpA14; _alloy: Np 0.2, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 10; `ORC-UCH5KWJ6UG.09ece2` |  |
| sm contribution; _printed: S°298 (el.)_ | 3.4 J/mol (basis unstated)/K | 298.15 | NpA14; _alloy: Np 0.2, Pu 0, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 10; `ORC-UCH5KWJ6UG.12ad98` |  |
| sm contribution; _printed: S°298 (el.)_ | 4.3 J/mol (basis unstated)/K | 298.15 | PuA12; _alloy: Np 0, Pu 0.333333, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 3; `ORC-EXMKTYQAEE.44feed` |  |
| sm contribution; _printed: S°298 (ph.)_ | 105.3 J/mol (basis unstated)/K | 298.15 | PuA12; _alloy: Np 0, Pu 0.333333, U 0_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 3; `ORC-EXMKTYQAEE.ec316c` |  |
| sm contribution; _printed: S°298 (el.)_ | 4.5 J/mol (basis unstated)/K | 298.15 | UA12; _alloy: Np 0, Pu 0, U 0.333333_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 1; `ORC-MZ2XRS7TQV.43a85d` |  |
| sm contribution; _printed: S°298 (ph.)_ | 101.2 J/mol (basis unstated)/K | 298.15 | UA12; _alloy: Np 0, Pu 0, U 0.333333_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 1; `ORC-MZ2XRS7TQV.98eaa3` |  |
| sm contribution; _printed: S°298 (ph.)_ | 117.5 J/mol (basis unstated)/K | 298.15 | UA13; _alloy: Np 0, Pu 0, U 0.25_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 4; `ORC-OZIZ5AB43L.1ad986` |  |
| sm contribution; _printed: S°298 (el.)_ | 4.4 J/mol (basis unstated)/K | 298.15 | UA13; _alloy: Np 0, Pu 0, U 0.25_ | DFT | [1] Sedmidubský 2010 | Table 2, p. 3, row 4; `ORC-OZIZ5AB43L.981b2d` |  |

## Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

1. D. Sedmidubský, R.J.M. Konings, P. Souček, Ab-initio calculations and phase diagram assessments of An–Al systems (An= U, Np, Pu), Journal of Nuclear Materials 397, 1-7 (2010). [doi:10.1016/j.jnucmat.2009.11.023](https://doi.org/10.1016/j.jnucmat.2009.11.023)

## 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 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); 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; 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).

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_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/).