Pb–U phases

8 phases (tier A 5, tier C 1, liquid 1, needs_review 1); 7 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 · full JSON · Pb–U system page · Markdown · field reference

Phases of the Pb–U system (8)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
ORTHORHOMBIC_A20 phase:pb-u:a20-orthorhombic	alpha-U · A20 · oC4 · Cmcm (63)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–948.3 K, x(U) 0.99909–1	2	2
BCC_A2 phase:pb-u:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 1015.66–3999.24 K, x(U) 0.96035–1	4	2
FCC_A1 phase:pb-u:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–600.61 K, x(U) 0–0	2	2
HCP_A3 phase:pb-u:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 2 calculated diagram(s)	0	2
LIQUID phase:pb-u:liquid	liquid	liquid	stable in 2 of 2 calculated diagram(s): 600.61–4000 K, x(U) 0–1	11	2
PB3U_L12 phase:pb-u:pb3u-l12	AuCu3 · L1_2 · cP4 · Pm-3m (221)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–1490.37 K, x(U) 0.25–0.25	6	2
PBU phase:pb-u:pbu	PbU · tI8 · I4_1/amd (141)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 2 of 2 calculated diagram(s): 300–1557.76 K, x(U) 0.5–0.5	10	2
TETRAGONAL_U phase:pb-u:u-tetragonal		needs_review	stable in 2 of 2 calculated diagram(s): 923.3–1052.18 K, x(U) 0.99207–1	4	2

ORTHORHOMBIC_A20 (Pb–U)

Id: phase:pb-u:a20-orthorhombic; status assigned
Structure: alpha-U · A20 · oC4 · Cmcm (63); type st:a20-alpha-u-oc4; tier A: standard phase name; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300–948.3 K, x(U) 0.99909–1
Literature: 2 values (2 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pb-u:a20-orthorhombic, corpus:phase:pb-u:orthorhombic-a20
paper: paper:10.1016/j.jnucmat.2010.02.002:αU
tdb: tdb:PbU-10Li.tdb:ORTHORHOMBIC_A20, tdb:PbU-21Aga.tdb:ORTHORHOMBIC_A20

TDB models of ORTHORHOMBIC_A20 (2): PHASE and CONSTITUENT statements as written

PbU-10Li.tdb: ORTHORHOMBIC_A20, type code %, sha256 d7e91ddbf663d2cb…

41: PHASE ORTHORHOMBIC_A20 % 1 1 !
42: CONST ORTHORHOMBIC_A20 : PB U% : !

PbU-21Aga.tdb: ORTHORHOMBIC_A20, type code %, sha256 acb4f2362054d048…

42: PHASE ORTHORHOMBIC_A20 % 1 1 !
43: CONST ORTHORHOMBIC_A20 : PB U% : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2010.02.002 Z.S. Li, X.J. Liu, C.P. Wang, Thermodynamic modeling of the Pb–U and Pb–Pu systems, Journal of Nuclear Materials 403, 1-6 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/j.tca.2021.178913 Renu Agarwal, Understanding uranium interactions with bismuth and lead-bismuth eutectic: Using calorimetric measurements, Thermochimica Acta 699, 178913 (2021).
assessment that models this phase

BCC_A2 (Pb–U)

Id: phase:pb-u: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 2 of 2 calculated diagram(s): 1015.66–3999.24 K, x(U) 0.96035–1
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:pb-u:bcc-a2
paper: paper:10.1016/j.jnucmat.2010.02.002:γU
tdb: tdb:PbU-10Li.tdb:BCC_A2, tdb:PbU-21Aga.tdb:BCC_A2

TDB models of BCC_A2 (2): PHASE and CONSTITUENT statements as written

PbU-10Li.tdb: BCC_A2, type code %B, sha256 d7e91ddbf663d2cb…

31: PHASE BCC_A2 %B 2 1 3 !
32: CONST BCC_A2 : PB U% : VA : !

PbU-21Aga.tdb: BCC_A2, type code %B, sha256 acb4f2362054d048…

32: PHASE BCC_A2 %B 2 1 3 !
33: CONST BCC_A2 : PB U% : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2010.02.002 Z.S. Li, X.J. Liu, C.P. Wang, Thermodynamic modeling of the Pb–U and Pb–Pu systems, Journal of Nuclear Materials 403, 1-6 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/j.tca.2021.178913 Renu Agarwal, Understanding uranium interactions with bismuth and lead-bismuth eutectic: Using calorimetric measurements, Thermochimica Acta 699, 178913 (2021).
assessment that models this phase

FCC_A1 (Pb–U)

Id: phase:pb-u: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 2 of 2 calculated diagram(s): 300–600.61 K, x(U) 0–0
Literature: 2 values (2 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:pb-u:fcc-a1
paper: paper:10.1016/j.jnucmat.2010.02.002:(Pb)
tdb: tdb:PbU-10Li.tdb:FCC_A1, tdb:PbU-21Aga.tdb:FCC_A1

TDB models of FCC_A1 (2): PHASE and CONSTITUENT statements as written

PbU-10Li.tdb: FCC_A1, type code %A, sha256 d7e91ddbf663d2cb…

26: PHASE FCC_A1 %A 2 1 1 !
27: CONST FCC_A1 : PB% U : VA : !

PbU-21Aga.tdb: FCC_A1, type code %A, sha256 acb4f2362054d048…

27: PHASE FCC_A1 %A 2 1 1 !
28: CONST FCC_A1 : PB% U : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2010.02.002 Z.S. Li, X.J. Liu, C.P. Wang, Thermodynamic modeling of the Pb–U and Pb–Pu systems, Journal of Nuclear Materials 403, 1-6 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/j.tca.2021.178913 Renu Agarwal, Understanding uranium interactions with bismuth and lead-bismuth eutectic: Using calorimetric measurements, Thermochimica Acta 699, 178913 (2021).
assessment that models this phase

HCP_A3 (Pb–U)

Id: phase:pb-u:hcp-a3; status assigned
Structure: Mg · A3 · hP2 · P6_3/mmc (194); type st:a3-mg-hp2; tier A: standard phase name; confidence high
Stability: not stable in 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:pb-u:hcp-a3
tdb: tdb:PbU-10Li.tdb:HCP_A3, tdb:PbU-21Aga.tdb:HCP_A3

TDB models of HCP_A3 (2): PHASE and CONSTITUENT statements as written

PbU-10Li.tdb: HCP_A3, type code %A, sha256 d7e91ddbf663d2cb…

36: PHASE HCP_A3 %A 2 1 0.5 !
37: CONST HCP_A3 : PB U : VA: !

PbU-21Aga.tdb: HCP_A3, type code %A, sha256 acb4f2362054d048…

37: PHASE HCP_A3 %A 2 1 0.5 !
38: CONST HCP_A3 : PB U : VA: !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2010.02.002 Z.S. Li, X.J. Liu, C.P. Wang, Thermodynamic modeling of the Pb–U and Pb–Pu systems, Journal of Nuclear Materials 403, 1-6 (2010).
assessment that models this phase
doi:10.1016/j.tca.2021.178913 Renu Agarwal, Understanding uranium interactions with bismuth and lead-bismuth eutectic: Using calorimetric measurements, Thermochimica Acta 699, 178913 (2021).
assessment that models this phase

LIQUID (Pb–U)

Id: phase:pb-u:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 600.61–4000 K, x(U) 0–1
Literature: 11 values (11 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pb-u:liquid
paper: paper:10.1016/j.jnucmat.2010.02.002:L, paper:10.1016/j.jnucmat.2010.02.002:L2
tdb: tdb:PbU-10Li.tdb:LIQUID, tdb:PbU-21Aga.tdb:LIQUID

TDB models of LIQUID (2): PHASE and CONSTITUENT statements as written

PbU-10Li.tdb: LIQUID, type code %, sha256 d7e91ddbf663d2cb…

21: PHASE LIQUID:L % 1 1 !
22: CONST LIQUID:L : PB U : !

PbU-21Aga.tdb: LIQUID, type code %, sha256 acb4f2362054d048…

22: PHASE LIQUID:L % 1 1 !
23: CONST LIQUID:L : PB U : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2010.02.002 Z.S. Li, X.J. Liu, C.P. Wang, Thermodynamic modeling of the Pb–U and Pb–Pu systems, Journal of Nuclear Materials 403, 1-6 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/j.tca.2021.178913 Renu Agarwal, Understanding uranium interactions with bismuth and lead-bismuth eutectic: Using calorimetric measurements, Thermochimica Acta 699, 178913 (2021).
assessment that models this phase

PB3U_L12 (Pb–U)

Id: phase:pb-u:pb3u-l12; status assigned
Structure: AuCu3 · L1_2 · cP4 · Pm-3m (221); type st:l1-2-aucu3-cp4; tier A: standard phase name; confidence high
Stoichiometry: Pb 0.7500, U 0.2500
Stability: stable in 2 of 2 calculated diagram(s): 300–1490.37 K, x(U) 0.25–0.25
Literature: 6 values (6 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:pb-u:pb3u-l12
paper: paper:10.1016/j.jnucmat.2010.02.002:Pb3U
tdb: tdb:PbU-10Li.tdb:PB3U_L12, tdb:PbU-21Aga.tdb:PB3U_L12

TDB models of PB3U_L12 (2): PHASE and CONSTITUENT statements as written

PbU-10Li.tdb: PB3U_L12, type code %, sha256 d7e91ddbf663d2cb…

51: PHASE PB3U_L12 % 2 3 1 !
52: CONST PB3U_L12 : PB : U : !

PbU-21Aga.tdb: PB3U_L12, type code %, sha256 acb4f2362054d048…

52: PHASE PB3U_L12 % 2 3 1 !
53: CONST PB3U_L12 : PB : U : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2010.02.002 Z.S. Li, X.J. Liu, C.P. Wang, Thermodynamic modeling of the Pb–U and Pb–Pu systems, Journal of Nuclear Materials 403, 1-6 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/j.tca.2021.178913 Renu Agarwal, Understanding uranium interactions with bismuth and lead-bismuth eutectic: Using calorimetric measurements, Thermochimica Acta 699, 178913 (2021).
assessment that models this phase

PBU (Pb–U)

Id: phase:pb-u:pbu; status assigned
Structure: PbU · tI8 · I4_1/amd (141); type st:pbu-ti8; 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
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: Pb 0.5000, U 0.5000
Stability: stable in 2 of 2 calculated diagram(s): 300–1557.76 K, x(U) 0.5–0.5
Literature: 10 values (10 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pb-u:pbu
paper: paper:10.1016/j.jnucmat.2010.02.002:PbU, paper:10.1016/j.jnucmat.2010.02.002:Pb–U
tdb: tdb:PbU-10Li.tdb:PBU, tdb:PbU-21Aga.tdb:PBU

TDB models of PBU (2): PHASE and CONSTITUENT statements as written

PbU-10Li.tdb: PBU, type code %, sha256 d7e91ddbf663d2cb…

56: PHASE PBU % 2 1 1 !
57: CONST PBU : PB : U : !

PbU-21Aga.tdb: PBU, type code %, sha256 acb4f2362054d048…

57: PHASE PBU % 2 1 1 !
58: CONST PBU : PB : U : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2010.02.002 Z.S. Li, X.J. Liu, C.P. Wang, Thermodynamic modeling of the Pb–U and Pb–Pu systems, Journal of Nuclear Materials 403, 1-6 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/j.tca.2021.178913 Renu Agarwal, Understanding uranium interactions with bismuth and lead-bismuth eutectic: Using calorimetric measurements, Thermochimica Acta 699, 178913 (2021).
assessment that models this phase

TETRAGONAL_U (Pb–U)

Id: phase:pb-u:u-tetragonal; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:TETRAGONAL; no_structure_token
Candidate (sgte_mmc2): beta-U · A_b · tP30 · P4_2/mnm (136) — Hallstedt 2025 mmc2 row for TETRAGONAL_U: beta-U
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — PbU-10Li.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — PbU-21Aga.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Stability: stable in 2 of 2 calculated diagram(s): 923.3–1052.18 K, x(U) 0.99207–1
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pb-u:u-tetragonal, corpus:phase:pb-u:tetragonal-u
paper: paper:10.1016/j.jnucmat.2010.02.002:βU
tdb: tdb:PbU-10Li.tdb:TETRAGONAL_U, tdb:PbU-21Aga.tdb:TETRAGONAL_U

TDB models of TETRAGONAL_U (2): PHASE and CONSTITUENT statements as written

PbU-10Li.tdb: TETRAGONAL_U, type code %, sha256 d7e91ddbf663d2cb…

46: PHASE TETRAGONAL_U % 1 1 !
47: CONST TETRAGONAL_U : PB U% : !

PbU-21Aga.tdb: TETRAGONAL_U, type code %, sha256 acb4f2362054d048…

47: PHASE TETRAGONAL_U % 1 1 !
48: CONST TETRAGONAL_U : PB U% : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2010.02.002 Z.S. Li, X.J. Liu, C.P. Wang, Thermodynamic modeling of the Pb–U and Pb–Pu systems, Journal of Nuclear Materials 403, 1-6 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/j.tca.2021.178913 Renu Agarwal, Understanding uranium interactions with bismuth and lead-bismuth eutectic: Using calorimetric measurements, Thermochimica Acta 699, 178913 (2021).
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). doi: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). doi: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.

@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}
}