# La–Pb phases

> La–Pb system: 12 phases (tier A 7, tier C 2, liquid 1, needs_review 2); 11 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/LA-PB.html · Markdown: https://data.orchid-project.org/phases/pages/LA-PB.md

12 phases (tier A 7, tier C 2, liquid 1, needs_review 2); 11 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=LA-PB) · [full JSON](https://data.orchid-project.org/phases/systems/LA-PB.json) · [La–Pb system page](https://data.orchid-project.org/systems/LA-PB.html) · [Markdown](https://data.orchid-project.org/phases/pages/LA-PB.md) · [field reference](https://data.orchid-project.org/phases/SCHEMA.md)

Table: Phases of the La–Pb system (12)

| Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models |
|---|---|---|---|---:|---:|
| [BCC_A2](#phase-la-pb-bcc-a2); _phase:la-pb:bcc-a2_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 1112.89–1202.89 K, x(Pb) 0–0.0133 | 0 | 1 |
| [DHCP](#phase-la-pb-dhcp-a3); _phase:la-pb:dhcp-a3_ | alpha-La · A3' · hP4 · P6_3/mmc (194) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–762.49 K, x(Pb) 0–0 | 0 | 1 |
| [FCC_A1](#phase-la-pb-fcc-a1); _phase:la-pb:fcc-a1_ | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1134 K, x(Pb) 0–1 | 0 | 1 |
| [HCP_A3](#phase-la-pb-hcp-a3); _phase:la-pb:hcp-a3_ | Mg · A3 · hP2 · P6_3/mmc (194) | tier A: standard phase name | not stable in 1 calculated diagram(s) | 0 | 1 |
| [LA3PB4_HT](#phase-la-pb-la3pb4-ht); _phase:la-pb:la3pb4-ht_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 988.02–1457.71 K, x(Pb) 0.57143–0.57143 | 0 | 1 |
| [LA3PB4_LT](#phase-la-pb-la3pb4-lt); _phase:la-pb:la3pb4-lt_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 300–988.02 K, x(Pb) 0.57143–0.57143 | 0 | 1 |
| [LA4PB3_D73](#phase-la-pb-la4pb3-d73); _phase:la-pb:la4pb3-d73_ | Th3P4 · D7_3 · cI28 · I-43d (220) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1691.7 K, x(Pb) 0.42857–0.42857 | 0 | 1 |
| [LA5PB3_D88](#phase-la-pb-la5pb3-d88); _phase:la-pb:la5pb3-d88_ | Mn5Si3 · D8_8 · hP16 · P6_3/mcm (193) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1726.13 K, x(Pb) 0.375–0.375 | 0 | 1 |
| [LA5PB4](#phase-la-pb-la5pb4); _phase:la-pb:la5pb4_ | Ge4Sm5 · oP36 · Pnma (62) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 1 of 1 calculated diagram(s): 300–1623.75 K, x(Pb) 0.44444–0.44444 | 0 | 1 |
| [LAPB2](#phase-la-pb-lapb2); _phase:la-pb:lapb2_ | CuZr2 · tI6 · I4/mmm (139) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 1 of 1 calculated diagram(s): 300–1371.83 K, x(Pb) 0.66667–0.66667 | 0 | 1 |
| [LAPB3_L12](#phase-la-pb-lapb3-l12); _phase:la-pb:lapb3-l12_ | AuCu3 · L1_2 · cP4 · Pm-3m (221) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1436.97 K, x(Pb) 0.75–0.75 | 0 | 1 |
| [LIQUID](#phase-la-pb-liquid); _phase:la-pb:liquid_ | liquid | liquid | stable in 1 of 1 calculated diagram(s): 588.3–2500 K, x(Pb) 0–1 | 0 | 1 |

## BCC_A2 (La–Pb)

- Id: `phase:la-pb:bcc-a2`; 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): 1112.89–1202.89 K, x(Pb) 0–0.0133
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:bcc-a2)

Names (2): _corpus: _corpus:phase:la-pb:bcc-a2  
_tdb: _tdb:LaPb-09Idb.tdb:BCC_A2  


### TDB models of BCC_A2 (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): BCC_A2, type code %B, sha256 `ee98d00c51140961…`

~~~~text
30: PHASE BCC_A2 %B 2 1 3 !
31: CONST BCC_A2 : LA% PB : VA : !
~~~~

## DHCP (La–Pb)

- Id: `phase:la-pb:dhcp-a3`; status `assigned`
- Structure: alpha-La · A3' · hP4 · P6_3/mmc (194); type `st:a3-alpha-la-hp4`; tier A: standard phase name; confidence high
- Stoichiometry: La 1.0000
- Stability: stable in 1 of 1 calculated diagram(s): 300–762.49 K, x(Pb) 0–0
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:dhcp-a3)

Names (2): _corpus: _corpus:phase:la-pb:dhcp-a3  
_tdb: _tdb:LaPb-09Idb.tdb:DHCP  


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

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): DHCP, type code %, sha256 `ee98d00c51140961…`

~~~~text
40: PHASE DHCP % 1 1 !
41: CONST DHCP : LA : !
~~~~

## FCC_A1 (La–Pb)

- Id: `phase:la-pb: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): 300–1134 K, x(Pb) 0–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:fcc-a1)

Names (2): _corpus: _corpus:phase:la-pb:fcc-a1  
_tdb: _tdb:LaPb-09Idb.tdb:FCC_A1  


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

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): FCC_A1, type code %A, sha256 `ee98d00c51140961…`

~~~~text
25: PHASE FCC_A1 %A 2 1 1 !
26: CONST FCC_A1 : LA% PB% : VA : !
~~~~

## HCP_A3 (La–Pb)

- Id: `phase:la-pb:hcp-a3`; status `assigned`
- Structure: Mg · A3 · hP2 · P6_3/mmc (194); type `st:a3-mg-hp2`; tier A: standard phase name; confidence high
- Stoichiometry: Pb 1.0000
- Stability: not stable in 1 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:hcp-a3)

Names (2): _corpus: _corpus:phase:la-pb:hcp-a3  
_tdb: _tdb:LaPb-09Idb.tdb:HCP_A3  


### TDB models of HCP_A3 (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): HCP_A3, type code %A, sha256 `ee98d00c51140961…`

~~~~text
35: PHASE HCP_A3 %A 2 1 0.5 !
36: CONST HCP_A3 : PB : VA : !
~~~~

## LA3PB4_HT (La–Pb)

- Id: `phase:la-pb:la3pb4-ht`; status `needs_review`
- No structure assigned. Why: no_structure_token; polymorph_family:other phases of this system have the same composition; sgte_mmc2_row_incomplete
- Candidate (dft_oqmd): Cmcm (63) — on-hull OQMD La3 Pb4 at x(PB)=0.5714
- Candidate (sgte_mmc2): (La3Pb4-ht) — Hallstedt 2025 mmc2 row for LA3PB4_HT: La3Pb4 (high T)
- Stoichiometry: La 0.4286, Pb 0.5714
- Stability: stable in 1 of 1 calculated diagram(s): 988.02–1457.71 K, x(Pb) 0.57143–0.57143
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:la3pb4-ht)

Names (2): _corpus: _corpus:phase:la-pb:la3pb4-ht  
_tdb: _tdb:LaPb-09Idb.tdb:LA3PB4_HT  


### TDB models of LA3PB4_HT (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): LA3PB4_HT, type code %, sha256 `ee98d00c51140961…`

~~~~text
65: PHASE LA3PB4_HT % 2 3 4 !
66: CONST LA3PB4_HT : LA : PB : !
~~~~

## LA3PB4_LT (La–Pb)

- Id: `phase:la-pb:la3pb4-lt`; status `needs_review`
- No structure assigned. Why: no_structure_token; polymorph_family:other phases of this system have the same composition; sgte_mmc2_row_incomplete
- Candidate (dft_oqmd): Cmcm (63) — on-hull OQMD La3 Pb4 at x(PB)=0.5714
- Candidate (sgte_mmc2): (La3Pb4-lt) — Hallstedt 2025 mmc2 row for LA3PB4_LT: La3Pb4 (low T)
- Stoichiometry: La 0.4286, Pb 0.5714
- Stability: stable in 1 of 1 calculated diagram(s): 300–988.02 K, x(Pb) 0.57143–0.57143
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:la3pb4-lt)

Names (2): _corpus: _corpus:phase:la-pb:la3pb4-lt  
_tdb: _tdb:LaPb-09Idb.tdb:LA3PB4_LT  


### TDB models of LA3PB4_LT (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): LA3PB4_LT, type code %, sha256 `ee98d00c51140961…`

~~~~text
60: PHASE LA3PB4_LT % 2 3 4 !
61: CONST LA3PB4_LT : LA : PB : !
~~~~

## LA4PB3_D73 (La–Pb)

- Id: `phase:la-pb:la4pb3-d73`; status `assigned`
- Structure: Th3P4 · D7_3 · cI28 · I-43d (220); type `st:d7-3-th3p4-ci28`; tier A: standard phase name; confidence high
- Caveat: DFT agrees: on-hull mp-aaabgnem and oqmd-30655, space group 220
- Stoichiometry: La 0.5714, Pb 0.4286
- Stability: stable in 1 of 1 calculated diagram(s): 300–1691.7 K, x(Pb) 0.42857–0.42857
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:la4pb3-d73)

Names (4): _corpus: _corpus:phase:la-pb:la4pb3-d73  
_mp: _mp:mp-aaabgnem  
_oqmd: _oqmd:oqmd-30655  
_tdb: _tdb:LaPb-09Idb.tdb:LA4PB3_D73  


### TDB models of LA4PB3_D73 (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): LA4PB3_D73, type code %, sha256 `ee98d00c51140961…`

~~~~text
50: PHASE LA4PB3_D73 % 2 4 3 !
51: CONST LA4PB3_D73 : LA : PB : !
~~~~

## LA5PB3_D88 (La–Pb)

- Id: `phase:la-pb:la5pb3-d88`; status `assigned`
- Structure: Mn5Si3 · D8_8 · hP16 · P6_3/mcm (193); type `st:d8-8-mn5si3-hp16`; tier A: standard phase name; confidence high
- Caveat: DFT agrees: on-hull mp-aaackxym and oqmd-31337, space group 193
- Stoichiometry: La 0.6250, Pb 0.3750
- Stability: stable in 1 of 1 calculated diagram(s): 300–1726.13 K, x(Pb) 0.375–0.375
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:la5pb3-d88)

Names (4): _corpus: _corpus:phase:la-pb:la5pb3-d88  
_mp: _mp:mp-aaackxym  
_oqmd: _oqmd:oqmd-31337  
_tdb: _tdb:LaPb-09Idb.tdb:LA5PB3_D88  


### TDB models of LA5PB3_D88 (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): LA5PB3_D88, type code %, sha256 `ee98d00c51140961…`

~~~~text
45: PHASE LA5PB3_D88 % 2 5 3 !
46: CONST LA5PB3_D88 : LA : PB : !
~~~~

## LA5PB4 (La–Pb)

- Id: `phase:la-pb:la5pb4`; status `assigned`
- Structure: Ge4Sm5 · oP36 · Pnma (62); type `st:ge4sm5-op36`; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
- Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) [doi:10.1016/j.calphad.2025.102833](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (dft_space_group_62_matches_2_structure_types, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stoichiometry: La 0.5556, Pb 0.4444
- Stability: stable in 1 of 1 calculated diagram(s): 300–1623.75 K, x(Pb) 0.44444–0.44444
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:la5pb4)

Names (2): _corpus: _corpus:phase:la-pb:la5pb4  
_tdb: _tdb:LaPb-09Idb.tdb:LA5PB4  


### TDB models of LA5PB4 (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): LA5PB4, type code %, sha256 `ee98d00c51140961…`

~~~~text
55: PHASE LA5PB4 % 2 5 4 !
56: CONST LA5PB4 : LA : PB : !
~~~~

## LAPB2 (La–Pb)

- Id: `phase:la-pb:lapb2`; status `assigned`
- Structure: CuZr2 · tI6 · I4/mmm (139); type `st:cuzr2-ti6`; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
- Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) [doi:10.1016/j.calphad.2025.102833](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stoichiometry: La 0.3333, Pb 0.6667
- Stability: stable in 1 of 1 calculated diagram(s): 300–1371.83 K, x(Pb) 0.66667–0.66667
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:lapb2)

Names (2): _corpus: _corpus:phase:la-pb:lapb2  
_tdb: _tdb:LaPb-09Idb.tdb:LAPB2  


### TDB models of LAPB2 (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): LAPB2, type code %, sha256 `ee98d00c51140961…`

~~~~text
70: PHASE LAPB2 % 2 1 2 !
71: CONST LAPB2 : LA : PB : !
~~~~

## LAPB3_L12 (La–Pb)

- Id: `phase:la-pb:lapb3-l12`; status `assigned`
- Structure: AuCu3 · L1_2 · cP4 · Pm-3m (221); type `st:l1-2-aucu3-cp4`; tier A: standard phase name; confidence high
- Caveat: DFT agrees: on-hull mp-aaaabfsi and oqmd-17568, space group 221
- Stoichiometry: La 0.2500, Pb 0.7500
- Stability: stable in 1 of 1 calculated diagram(s): 300–1436.97 K, x(Pb) 0.75–0.75
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:lapb3-l12)

Names (4): _corpus: _corpus:phase:la-pb:lapb3-l12  
_mp: _mp:mp-aaaabfsi  
_oqmd: _oqmd:oqmd-17568  
_tdb: _tdb:LaPb-09Idb.tdb:LAPB3_L12  


### TDB models of LAPB3_L12 (1): PHASE and CONSTITUENT statements as written

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): LAPB3_L12, type code %, sha256 `ee98d00c51140961…`

~~~~text
75: PHASE LAPB3_L12 % 2 1 3 !
76: CONST LAPB3_L12 : LA : PB : !
~~~~

## LIQUID (La–Pb)

- Id: `phase:la-pb:liquid`; status `assigned`
- Structure: liquid; type `st:liquid`; liquid; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 588.3–2500 K, x(Pb) 0–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:la-pb:liquid)

Names (2): _corpus: _corpus:phase:la-pb:liquid  
_tdb: _tdb:LaPb-09Idb.tdb:LIQUID  


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

[LaPb-09Idb.tdb](https://orchid-project.org/data/databases/sgte-binary/LaPb-09Idb.tdb): LIQUID, type code %, sha256 `ee98d00c51140961…`

~~~~text
20: PHASE LIQUID:L % 1 1 !
21: CONST LIQUID:L : LA PB : !
~~~~

## 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).