# Pu–Th phases

> Pu–Th system: 9 phases (tier A 4, liquid 1, needs_review 4); 9 stable in a calculated diagram in the ORCHID phase registry, with names, structure type when the stored evidence supports an assignment under the stated tier rules, calculated stability, verbatim TDB PHASE/CONSTITUENT statements and example references.

HTML: https://data.orchid-project.org/phases/pages/PU-TH.html · Markdown: https://data.orchid-project.org/phases/pages/PU-TH.md

9 phases (tier A 4, liquid 1, needs_review 4); 9 stable in a calculated diagram. Structure types are assigned only when the stored evidence supports an assignment under the stated tier rules (tier A: standard phase name; tier B: unique Materials Project + OQMD on-hull match, DFT-supported; tier C: one structure stated by the assessment's crystallographic table, assessor-stated); other phases list candidates and are marked needs_review. Stability is from phase diagrams calculated with pycalphad from the SGTE binary collection (evidence class: model).

Data: [interactive registry](https://orchid-project.org/phases/?q=PU-TH) · [full JSON](https://data.orchid-project.org/phases/systems/PU-TH.json) · [Pu–Th system page](https://data.orchid-project.org/systems/PU-TH.html) · [Markdown](https://data.orchid-project.org/phases/pages/PU-TH.md) · [field reference](https://data.orchid-project.org/phases/SCHEMA.md)

Table: Phases of the Pu–Th system (9)

| Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models |
|---|---|---|---|---:|---:|
| [TETRAGONAL_A6](#phase-pu-th-a6-tetragonal); _phase:pu-th:a6-tetragonal_ | In · A6 · tI2 · I4/mmm (139) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 699.1–764.1 K, x(Th) 0–0.01149 | 0 | 1 |
| [FCC_A1](#phase-pu-th-fcc-a1); _phase:pu-th:fcc-a1_ | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1633.19 K, x(Th) 0–1 | 0 | 1 |
| [LIQUID](#phase-pu-th-liquid); _phase:pu-th:liquid_ | liquid | liquid | stable in 1 of 1 calculated diagram(s): 838.82–4000 K, x(Th) 0–1 | 0 | 1 |
| [ALPHA_PU](#phase-pu-th-pu-alpha); _phase:pu-th:pu-alpha_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 300–397.62 K, x(Th) 0–0 | 0 | 1 |
| [BCC_PU](#phase-pu-th-pu-bcc); _phase:pu-th:pu-bcc_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 753.1–913 K, x(Th) 0–0.03412 | 0 | 1 |
| [BETA_PU](#phase-pu-th-pu-beta); _phase:pu-th:pu-beta_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 397.62–487.9 K, x(Th) 0–0 | 0 | 1 |
| [GAMMA_PU](#phase-pu-th-pu-gamma); _phase:pu-th:pu-gamma_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 487.9–788.55 K, x(Th) 0–0 | 0 | 1 |
| [PU7TH3](#phase-pu-th-pu7th3); _phase:pu-th:pu7th3_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 300–883 K, x(Th) 0.3–0.3 | 0 | 1 |
| [BCC_TH](#phase-pu-th-th-bcc); _phase:pu-th:th-bcc_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 877.78–3999.24 K, x(Th) 0.46549–1 | 0 | 1 |

## TETRAGONAL_A6 (Pu–Th)

- Id: `phase:pu-th:a6-tetragonal`; status `assigned`
- Structure: In · A6 · tI2 · I4/mmm (139); type `st:a6-in-ti2`; tier A: standard phase name; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 699.1–764.1 K, x(Th) 0–0.01149
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:a6-tetragonal)

Names (2): _corpus: _corpus:phase:pu-th:a6-tetragonal  
_tdb: _tdb:PuTh-14Ben.tdb:TETRAGONAL_A6  


### TDB models of TETRAGONAL_A6 (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): TETRAGONAL_A6, type code %, sha256 `90a9babb3ad9d9a5…`

~~~~text
54: PHASE TETRAGONAL_A6 % 1 1 !
55: CONST TETRAGONAL_A6 : PU% TH : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## FCC_A1 (Pu–Th)

- Id: `phase:pu-th:fcc-a1`; status `assigned`
- Structure: Cu · A1 · cF4 · Fm-3m (225); type `st:a1-cu-cf4`; tier A: standard phase name; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 300–1633.19 K, x(Th) 0–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:fcc-a1)

Names (2): _corpus: _corpus:phase:pu-th:fcc-a1  
_tdb: _tdb:PuTh-14Ben.tdb:FCC_A1  


### TDB models of FCC_A1 (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): FCC_A1, type code %A, sha256 `90a9babb3ad9d9a5…`

~~~~text
34: PHASE FCC_A1 %A 2 1 1 !
35: CONST FCC_A1 : PU% TH% : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## LIQUID (Pu–Th)

- Id: `phase:pu-th:liquid`; status `assigned`
- Structure: liquid; type `st:liquid`; liquid; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 838.82–4000 K, x(Th) 0–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:liquid)

Names (2): _corpus: _corpus:phase:pu-th:liquid  
_tdb: _tdb:PuTh-14Ben.tdb:LIQUID  


### TDB models of LIQUID (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): LIQUID, type code %, sha256 `90a9babb3ad9d9a5…`

~~~~text
29: PHASE LIQUID:L % 1 1 !
30: CONST LIQUID:L : PU TH : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## ALPHA_PU (Pu–Th)

- Id: `phase:pu-th:pu-alpha`; status `needs_review`
- No structure assigned. Why: no_structure_token; unary_composition
- Candidate (sgte_mmc2): alpha-Pu · mP16 · P2_1/m (11) — Hallstedt 2025 mmc2 row for ALPHA_PU: Pu (alpha)
- Candidate (tdb_comment): alpha-Pu · mP16 · P2_1/m — PuTh-14Ben.tdb: 'Prototype alpha-Pu (mP16, P2_1/m)'
- Stoichiometry: Pu 1.0000
- Stability: stable in 1 of 1 calculated diagram(s): 300–397.62 K, x(Th) 0–0
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:pu-alpha)

Names (2): _corpus: _corpus:phase:pu-th:pu-alpha  
_tdb: _tdb:PuTh-14Ben.tdb:ALPHA_PU  


### TDB models of ALPHA_PU (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): ALPHA_PU, type code %, sha256 `90a9babb3ad9d9a5…`

~~~~text
59: PHASE ALPHA_PU % 1 1 !
60: CONST ALPHA_PU : PU% : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## BCC_PU (Pu–Th)

- Id: `phase:pu-th:pu-bcc`; status `assigned`
- Structure: W · A2 · cI2 · Im-3m (229); type `st:a2-w-ci2`; tier A: standard phase name; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 753.1–913 K, x(Th) 0–0.03412
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:pu-bcc)

Names (2): _corpus: _corpus:phase:pu-th:pu-bcc  
_tdb: _tdb:PuTh-14Ben.tdb:BCC_PU  


### TDB models of BCC_PU (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): BCC_PU, type code %B, sha256 `90a9babb3ad9d9a5…`

~~~~text
44: PHASE BCC_PU %B 2 1 3 !
45: CONST BCC_PU : PU% TH : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## BETA_PU (Pu–Th)

- Id: `phase:pu-th:pu-beta`; status `needs_review`
- No structure assigned. Why: no_structure_token; unary_composition
- Candidate (sgte_mmc2): beta-Pu · mC34 · C2/m (12) — Hallstedt 2025 mmc2 row for BETA_PU: Pu (beta)
- Candidate (tdb_comment): beta-Pu · mC34 · C2/m — PuTh-14Ben.tdb: 'Prototype beta-Pu (mC34, C2/m)'
- Stoichiometry: Pu 1.0000
- Stability: stable in 1 of 1 calculated diagram(s): 397.62–487.9 K, x(Th) 0–0
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:pu-beta)

Names (2): _corpus: _corpus:phase:pu-th:pu-beta  
_tdb: _tdb:PuTh-14Ben.tdb:BETA_PU  


### TDB models of BETA_PU (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): BETA_PU, type code %, sha256 `90a9babb3ad9d9a5…`

~~~~text
64: PHASE BETA_PU % 1 1 !
65: CONST BETA_PU : PU% : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## GAMMA_PU (Pu–Th)

- Id: `phase:pu-th:pu-gamma`; status `needs_review`
- No structure assigned. Why: no_structure_token; unary_composition
- Candidate (sgte_mmc2): gamma-Pu · oF8 · Fddd (70) — Hallstedt 2025 mmc2 row for GAMMA_PU: Hg4In, Pu (gamma)
- Candidate (tdb_comment): gamma-Pu · oF8 · Fddd — PuTh-14Ben.tdb: 'Prototype gamma-Pu (oF8, Fddd)'
- Stoichiometry: Pu 1.0000
- Stability: stable in 1 of 1 calculated diagram(s): 487.9–788.55 K, x(Th) 0–0
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:pu-gamma)

Names (2): _corpus: _corpus:phase:pu-th:pu-gamma  
_tdb: _tdb:PuTh-14Ben.tdb:GAMMA_PU  


### TDB models of GAMMA_PU (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): GAMMA_PU, type code %, sha256 `90a9babb3ad9d9a5…`

~~~~text
69: PHASE GAMMA_PU % 1 1 !
70: CONST GAMMA_PU : PU% : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## PU7TH3 (Pu–Th)

- Id: `phase:pu-th:pu7th3`; status `needs_review`
- No structure assigned. Why: no_on_hull_entry_in_both; no_structure_token; sgte_mmc2_row_incomplete
- Candidate (sgte_mmc2): (Pu7Th3) — Hallstedt 2025 mmc2 row for PU7TH3: Pu7Th3
- Stoichiometry: Pu 0.7000, Th 0.3000
- Stability: stable in 1 of 1 calculated diagram(s): 300–883 K, x(Th) 0.3–0.3
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:pu7th3)

Names (2): _corpus: _corpus:phase:pu-th:pu7th3  
_tdb: _tdb:PuTh-14Ben.tdb:PU7TH3  


### TDB models of PU7TH3 (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): PU7TH3, type code %, sha256 `90a9babb3ad9d9a5…`

~~~~text
74: PHASE PU7TH3 % 2 7 3 !
75: CONST PU7TH3 : PU : TH : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## BCC_TH (Pu–Th)

- Id: `phase:pu-th:th-bcc`; status `assigned`
- Structure: W · A2 · cI2 · Im-3m (229); type `st:a2-w-ci2`; tier A: standard phase name; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 877.78–3999.24 K, x(Th) 0.46549–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:pu-th:th-bcc)

Names (2): _corpus: _corpus:phase:pu-th:th-bcc  
_tdb: _tdb:PuTh-14Ben.tdb:BCC_TH  


### TDB models of BCC_TH (1): PHASE and CONSTITUENT statements as written

[PuTh-14Ben.tdb](https://orchid-project.org/data/databases/sgte-binary/PuTh-14Ben.tdb): BCC_TH, type code %B, sha256 `90a9babb3ad9d9a5…`

~~~~text
49: PHASE BCC_TH %B 2 1 3 !
50: CONST BCC_TH : PU TH% : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014).  
_assessment that models this phase_

## Please cite

- R. Arróyave, J. Saal, D. Shin, ORCHID-Registry: phase registry of binary systems (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735970
- 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; 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); the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work).

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_registry_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Registry: phase registry of binary systems}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735970},
  url       = {https://doi.org/10.5281/zenodo.23735970},
  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 the ORCHID phase registry and the sources named on the page (TDB assessments, Hallstedt 2025, Materials Project, OQMD). TDB statements are quoted as written; parameter expressions are not reproduced. Field reference: [SCHEMA.md](https://data.orchid-project.org/phases/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt).