# U–O system

> U–O system: 0 accepted literature values (none) and 6 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

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

0 accepted literature values from 0 paper(s); 6 calculated phase diagram(s).

Data: [interactive phase diagram](https://orchid-project.org/phase-diagrams/#U-O/UO-02Che.json) · [Markdown](https://data.orchid-project.org/systems/U-O.md)

## Calculated phase diagrams

Binary phase diagrams calculated with pycalphad 0.11.2 from the SGTE binary collection (Hallstedt 2025, CC BY 4.0). Evidence class: model.

Table: Assessments with a calculated phase diagram

| TDB file | Assessment | SHA-256 | Links |
|---|---|---|---|
| UO-02Che.tdb | P.-Y. Chevalier, E. Fischer, B. Cheynet, J. Nucl. Mater., 303, 1-28(2002). [doi:10.1016/S0022-3115(02)00813-9](https://doi.org/10.1016/S0022-3115%2802%2900813-9) | `f43d17d1669f4d07dcba2a16599851bb7d8cc97cf42b9f7fcd1fe18d45d87ece` | [viewer](https://orchid-project.org/phase-diagrams/#U-O/UO-02Che.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/UO-02Che.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/UO-02Che.json) |
| UO-02Gue.tdb | C. Gueneau, M. Baichi, D. Labroche, C. Chatillon, B. Sundman, J. Nucl. Mater., 304, 161-75(2002). [doi:10.1016/S0022-3115(02)00878-4](https://doi.org/10.1016/S0022-3115%2802%2900878-4) | `dabf96b4fc2869745bb78b561f074e8e25c2ce3d15ac19a0b392debcbaaf5c61` | [viewer](https://orchid-project.org/phase-diagrams/#U-O/UO-02Gue.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/UO-02Gue.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/UO-02Gue.json) |
| UO-04Che.tdb | P.-Y. Chevalier, E. Fischer, B. Cheynet, Calphad, 28, 15-40(2004). [doi:10.1016/j.calphad.2004.03.005](https://doi.org/10.1016/j.calphad.2004.03.005) | `c929e68af28f01b244b50433ea6437becbc4bd879e0cfc285d5376050f8b145f` | [viewer](https://orchid-project.org/phase-diagrams/#U-O/UO-04Che.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/UO-04Che.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/UO-04Che.json) |
| UO-08Bar.tdb | M. Barrachin, P.-Y. Chevalier, B. Cheynet, E. Fischer, J. Nucl. Mater., 375, 397-409(2008). [doi:10.1016/j.jnucmat.2008.02.003](https://doi.org/10.1016/j.jnucmat.2008.02.003) | `9c0bd45c36c212ad50d8cb42d24641de2be59b7101a456773b1c1b112a962ac4` | [viewer](https://orchid-project.org/phase-diagrams/#U-O/UO-08Bar.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/UO-08Bar.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/UO-08Bar.json) |
| UO-11Gue.tdb | C. Gueneau, N. Dupin, B. Sundman, C. Martial, J.-C. Dumas, S. Gosse, S. Chatain, F. De Bruycker, D. Manara, R.J.M. Konings, J. Nucl. Mater., 419, 145-67(2011). [doi:10.1016/j.jnucmat.2011.07.033](https://doi.org/10.1016/j.jnucmat.2011.07.033) | `880201adec5fc9b23e6b96b082d9df79ff4066891805b77d528964846792e8ea` | [viewer](https://orchid-project.org/phase-diagrams/#U-O/UO-11Gue.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/UO-11Gue.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/UO-11Gue.json) |
| UO-23Jia.tdb | Y. Jiang, Y. He, W. Zheng, J. Zhang, D. Zhang, X. Lu, J. Nucl. Mater., 574, 154180(2023). [doi:10.1016/j.jnucmat.2022.154180](https://doi.org/10.1016/j.jnucmat.2022.154180) | `cdb48540c17b0ad40f5814b89d086bfb9970d06d23686aec4a5d548b05ab878a` | [viewer](https://orchid-project.org/phase-diagrams/#U-O/UO-23Jia.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/UO-23Jia.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/UO-23Jia.json) |

Table: Calculated three-phase invariants (model, mole fraction of the second component)

| TDB file | T (K) | Phases at the invariant |
|---|---:|---|
| UO-02Che.tdb | 3759.28 | LIQUID (x(O) 0.24101) + LIQUID#2 (x(O) 0.50136) + GAS (x(O) 0.5177) |
| UO-02Che.tdb | 3076.17 | UO2_C1 (x(O) 0.67429) + LIQUID (x(O) 0.67877) + GAS (x(O) 0.7782) |
| UO-02Che.tdb | 2692.09 | LIQUID#2 (x(O) 0.04021) + LIQUID (x(O) 0.58133) + UO2_C1 (x(O) 0.62609) |
| UO-02Che.tdb | 2155.29 | UO2_C1 (x(O) 0.69125) + U3O8 (x(O) 0.72727) + GAS (x(O) 0.98605) |
| UO-02Che.tdb | 1407.96 | BCC_A2 (x(O) 0) + LIQUID (x(O) 4.000e-5) + UO2_C1 (x(O) 0.66614) |
| UO-02Che.tdb | 1048.99 | TETRAGONAL_U (x(O) 0) + BCC_A2 (x(O) 0) + UO2_C1 (x(O) 0.66664) |
| UO-02Che.tdb | 942.02 | ORTHORHOMBIC_A20 (x(O) 0) + TETRAGONAL_U (x(O) 0) + UO2_C1 (x(O) 0.66666) |
| UO-02Che.tdb | 941.79 | U3O8 (x(O) 0.72727) + UO3 (x(O) 0.75) + GAS (x(O) 1) |
| UO-02Che.tdb | 941.79 | U3O8 (x(O) 0.72727) + UO3 (x(O) 0.75) + O2GAS (x(O) 1) |
| UO-02Gue.tdb | 2720.24 | UO2_C1 (x(O) 0.68528) + ION (x(O) 0.71928) + GAS (x(O) 0.87743) |
| UO-02Gue.tdb | 2718.6 | ION (x(O) 0.0404) + ION#2 (x(O) 0.59458) + UO2_C1 (x(O) 0.62826) |
| UO-02Gue.tdb | 2034.43 | UO2_C1 (x(O) 0.69355) + U3O8_S4 (x(O) 0.72727) + GAS (x(O) 0.99623) |
| UO-02Gue.tdb | 1407.99 | ION (x(O) 0) + BCC_A2 (x(O) 0) + UO2_C1 (x(O) 0.66554) |
| UO-02Gue.tdb | 1399.01 | UO2_C1 (x(O) 0.69144) + U4O9_S3 (x(O) 0.69231) + U3O8_S4 (x(O) 0.72727) |
| UO-02Gue.tdb | 1048.99 | BCC_A2 (x(O) 0) + TETRAGONAL_U (x(O) 0) + UO2_C1 (x(O) 0.66657) |
| UO-02Gue.tdb | 942.02 | ORTHORHOMBIC_A20 (x(O) 0) + TETRAGONAL_U (x(O) 0) + UO2_C1 (x(O) 0.66663) |
| UO-02Gue.tdb | 849.97 | UO2_C1 (x(O) 0.67781) + U4O9_S2 (x(O) 0.69231) + U4O9_S3 (x(O) 0.69231) |
| UO-02Gue.tdb | 849.97 | U4O9_S3 (x(O) 0.69231) + U4O9_S2 (x(O) 0.69231) + U3O8_S4 (x(O) 0.72727) |
| UO-02Gue.tdb | 830 | U4O9_S2 (x(O) 0.69231) + U3O8_S4 (x(O) 0.72727) + U3O8_S3 (x(O) 0.72727) |
| UO-02Gue.tdb | 568 | U4O9_S2 (x(O) 0.69231) + U3O8_S3 (x(O) 0.72727) + U3O8_S2 (x(O) 0.72727) |
| UO-02Gue.tdb | 483 | U4O9_S2 (x(O) 0.69231) + U3O8_S1 (x(O) 0.72727) + U3O8_S2 (x(O) 0.72727) |
| UO-02Gue.tdb | 348 | UO2_C1 (x(O) 0.66667) + U4O9_S1 (x(O) 0.69231) + U4O9_S2 (x(O) 0.69231) |
| UO-02Gue.tdb | 348 | U4O9_S1 (x(O) 0.69231) + U4O9_S2 (x(O) 0.69231) + U3O8_S1 (x(O) 0.72727) |
| UO-04Che.tdb | 3809.2 | LIQUID (x(O) 0.22008) + LIQUID#2 (x(O) 0.49689) + GAS (x(O) 0.50942) |
| UO-04Che.tdb | 3072.73 | UO2_C1 (x(O) 0.67442) + LIQUID (x(O) 0.67892) + GAS (x(O) 0.77846) |
| UO-04Che.tdb | 2698.43 | LIQUID#2 (x(O) 0.03774) + LIQUID (x(O) 0.58556) + UO2_C1 (x(O) 0.6245) |
| UO-04Che.tdb | 2152.67 | UO2_C1 (x(O) 0.69165) + U3O8 (x(O) 0.72727) + GAS (x(O) 0.98635) |
| UO-04Che.tdb | 1407.99 | BCC_A2 (x(O) 0) + LIQUID (x(O) 0) + UO2_C1 (x(O) 0.66619) |
| UO-04Che.tdb | 1048.99 | TETRAGONAL_U (x(O) 0) + BCC_A2 (x(O) 0) + UO2_C1 (x(O) 0.66665) |
| UO-04Che.tdb | 942.02 | ORTHORHOMBIC_A20 (x(O) 0) + TETRAGONAL_U (x(O) 0) + UO2_C1 (x(O) 0.66666) |
| UO-04Che.tdb | 941.79 | U3O8 (x(O) 0.72727) + UO3 (x(O) 0.75) + GAS (x(O) 1) |
| UO-04Che.tdb | 941.79 | U3O8 (x(O) 0.72727) + UO3 (x(O) 0.75) + O2GAS (x(O) 1) |
| UO-08Bar.tdb | 3809.21 | LIQUID (x(O) 0.22007) + LIQUID#2 (x(O) 0.49691) + GAS (x(O) 0.50942) |
| UO-08Bar.tdb | 2698.43 | LIQUID#2 (x(O) 0.03774) + LIQUID (x(O) 0.58556) + UO2_C1 (x(O) 0.6245) |
| UO-08Bar.tdb | 2673.5 | UO2_C1 (x(O) 0.6829) + LIQUID (x(O) 0.70746) + GAS (x(O) 0.85996) |
| UO-08Bar.tdb | 2152.2 | UO2_C1 (x(O) 0.69166) + U3O8 (x(O) 0.72727) + GAS (x(O) 0.98641) |
| UO-08Bar.tdb | 1407.99 | BCC_A2 (x(O) 0) + LIQUID (x(O) 0) + UO2_C1 (x(O) 0.66619) |
| UO-08Bar.tdb | 1048.99 | TETRAGONAL_U (x(O) 0) + BCC_A2 (x(O) 0) + UO2_C1 (x(O) 0.66665) |
| UO-08Bar.tdb | 942.02 | ORTHORHOMBIC_A20 (x(O) 0) + TETRAGONAL_U (x(O) 0) + UO2_C1 (x(O) 0.66666) |
| UO-08Bar.tdb | 941.79 | U3O8 (x(O) 0.72727) + UO3 (x(O) 0.75) + GAS (x(O) 1) |
| UO-08Bar.tdb | 941.79 | U3O8 (x(O) 0.72727) + UO3 (x(O) 0.75) + O2GAS (x(O) 1) |
| UO-11Gue.tdb | 2708.16 | ION (x(O) 0.03821) + ION#2 (x(O) 0.59649) + UO2_WILD (x(O) 0.62404) |
| UO-11Gue.tdb | 2522.7 | UO2_WILD (x(O) 0.68557) + ION (x(O) 0.73055) + GAS (x(O) 0.9349) |
| UO-11Gue.tdb | 2008.56 | UO2_WILD (x(O) 0.69156) + U3O8_S4 (x(O) 0.72727) + GAS (x(O) 0.99711) |
| UO-11Gue.tdb | 1407.99 | ION (x(O) 0) + BCC_A2 (x(O) 0) + UO2_WILD (x(O) 0.66571) |
| UO-11Gue.tdb | 1407.99 | BCC_A2 (x(O) 0) + ION (x(O) 0) + UO2_C1 (x(O) 0.66571) |
| UO-11Gue.tdb | 1404.17 | UO2_WILD (x(O) 0.69128) + U4O9_S3 (x(O) 0.69231) + U3O8_S4 (x(O) 0.72727) |
| UO-11Gue.tdb | 1404.17 | UO2_C1 (x(O) 0.69128) + U4O9_S3 (x(O) 0.69231) + U3O8_S4 (x(O) 0.72727) |
| UO-11Gue.tdb | 1048.99 | BCC_A2 (x(O) 0) + TETRAGONAL_U (x(O) 0) + UO2_WILD (x(O) 0.66655) |
| UO-11Gue.tdb | 1048.99 | TETRAGONAL_U (x(O) 0) + BCC_A2 (x(O) 0) + UO2_C1 (x(O) 0.66655) |
| UO-11Gue.tdb | 942.02 | ORTHORHOMBIC_A20 (x(O) 0) + TETRAGONAL_U (x(O) 0) + UO2_C1 (x(O) 0.66662) |
| UO-11Gue.tdb | 942.02 | TETRAGONAL_U (x(O) 0) + ORTHORHOMBIC_A20 (x(O) 0) + UO2_WILD (x(O) 0.66662) |
| UO-11Gue.tdb | 850 | UO2_C1 (x(O) 0.6777) + U4O9_S2 (x(O) 0.69231) + U4O9_S3 (x(O) 0.69231) |
| UO-11Gue.tdb | 850 | U4O9_S3 (x(O) 0.69231) + U4O9_S2 (x(O) 0.69231) + U3O8_S4 (x(O) 0.72727) |
| UO-11Gue.tdb | 850 | UO2_WILD (x(O) 0.6777) + U4O9_S3 (x(O) 0.69231) + U4O9_S2 (x(O) 0.69231) |
| UO-11Gue.tdb | 830 | U4O9_S2 (x(O) 0.69231) + U3O8_S4 (x(O) 0.72727) + U3O8_S3 (x(O) 0.72727) |
| UO-11Gue.tdb | 568 | U4O9_S2 (x(O) 0.69231) + U3O8_S3 (x(O) 0.72727) + U3O8_S2 (x(O) 0.72727) |
| UO-11Gue.tdb | 483 | U4O9_S2 (x(O) 0.69231) + U3O8_S1 (x(O) 0.72727) + U3O8_S2 (x(O) 0.72727) |
| UO-11Gue.tdb | 348 | UO2_C1 (x(O) 0.66671) + U4O9_S1 (x(O) 0.69231) + U4O9_S2 (x(O) 0.69231) |
| UO-11Gue.tdb | 348 | U4O9_S1 (x(O) 0.69231) + U4O9_S2 (x(O) 0.69231) + U3O8_S1 (x(O) 0.72727) |
| UO-11Gue.tdb | 348 | UO2_WILD (x(O) 0.66671) + U4O9_S2 (x(O) 0.69231) + U4O9_S1 (x(O) 0.69231) |
| UO-23Jia.tdb | 2682.78 | UO2_C1 (x(O) 0.68143) + LIQUID (x(O) 0.7072) + GAS (x(O) 0.85795) |
| UO-23Jia.tdb | 2653.82 | LIQUID (x(O) 0.02872) + LIQUID#2 (x(O) 0.57402) + UO2_C1 (x(O) 0.62425) |
| UO-23Jia.tdb | 2165.88 | UO2_C1 (x(O) 0.68832) + U3O8 (x(O) 0.72727) + GAS (x(O) 0.98476) |
| UO-23Jia.tdb | 1407.99 | BCC_A2 (x(O) 0) + LIQUID (x(O) 0) + UO2_C1 (x(O) 0.66654) |
| UO-23Jia.tdb | 1387.38 | UO2_C1 (x(O) 0.68868) + U4O9 (x(O) 0.69231) + U3O8 (x(O) 0.72727) |
| UO-23Jia.tdb | 1387.38 | UO2_C1 (x(O) 0.68868) + U4O9 (x(O) 0.69231) + U3O8 (x(O) 0.72727) |
| UO-23Jia.tdb | 1048.99 | TETRAGONAL_U (x(O) 0) + BCC_A2 (x(O) 0) + UO2_C1 (x(O) 0.66667) |
| UO-23Jia.tdb | 942.02 | ORTHORHOMBIC_A20 (x(O) 0) + TETRAGONAL_U (x(O) 0) + UO2_C1 (x(O) 0.66667) |
| UO-23Jia.tdb | 941.79 | U3O8 (x(O) 0.72727) + UO3 (x(O) 0.75) + GAS (x(O) 1) |
| UO-23Jia.tdb | 941.79 | U3O8 (x(O) 0.72727) + UO3 (x(O) 0.75) + O2GAS (x(O) 1) |

## Please cite

- R. Arróyave, J. Saal, D. Shin, ORCHID-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). https://doi.org/10.5281/zenodo.23735859
- 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 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; 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).

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_phase_diagrams_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Diagrams: calculated binary phase diagrams}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735859},
  url       = {https://doi.org/10.5281/zenodo.23735859}
}

@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/).