O–Pb phases

13 phases (tier A 5, tier C 3, liquid 2, gas 2, needs_review 1); 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 · full JSON · O–Pb system page · Markdown · field reference

Phases of the O–Pb system (13)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:o-pb:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 1 calculated diagram(s)	0	1
FCC_A1 phase:o-pb:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–515 K, x(O) 0–0	0	1
GAS phase:o-pb:gas	gas	gas	stable in 1 of 1 calculated diagram(s): 930.04–2019.02 K, x(O) 1e-05–1	0	1
HCP_A3 phase:o-pb:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 1 calculated diagram(s)	0	1
ION phase:o-pb:ion	liquid	liquid	stable in 1 of 1 calculated diagram(s): 1162.43–2019.02 K, x(O) 0–0.49856	0	1
LIQUID phase:o-pb:liquid	liquid	liquid	not stable in 1 calculated diagram(s)	0	1
O2GAS phase:o-pb:o2gas	gas	gas	stable in 1 of 1 calculated diagram(s): 300–315 K, x(O) 1–1	0	1
PB12O17 phase:o-pb:pb12o17		needs_review	stable in 1 of 1 calculated diagram(s): 300–325 K, x(O) 0.58621–0.58621	13	1
PB12O19 phase:o-pb:pb12o19	(Pb12O19) · mP62 · Pc (7)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	not stable in 1 calculated diagram(s)	18	1
PB3O4 phase:o-pb:pb3o4	Pb3O4-T · tP28 · P4_2/mbc (135)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–307 K, x(O) 0.57143–0.57143	0	1
PBO_B10 phase:o-pb:pbo-b10	PbO-L · B10 · tP4 · P4/nmm (129)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–515 K, x(O) 0.5–0.5	0	1
PBO_M phase:o-pb:pbo-m	PbO-M · oP8 · Pbcm (57)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 930.04–1152.54 K, x(O) 0.5–0.5	0	1
PBO2_C4 phase:o-pb:pbo2-c4	TiO2 · C4 · tP6 · P4_2/mnm (136)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–325 K, x(O) 0.66667–0.66667	10	1

BCC_A2 (O–Pb)

Id: phase:o-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: not stable in 1 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-pb:bcc-a2
tdb: tdb:PbO-98Ris-LB.tdb:BCC_A2

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

PbO-98Ris-LB.tdb: BCC_A2, type code %B, sha256 263b6f32a74f0f62…

54: PHASE BCC_A2 %B 2 1 3 !
55: CONST BCC_A2 : PB : O VA% : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

FCC_A1 (O–Pb)

Id: phase:o-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): 300–515 K, x(O) 0–0
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-pb:fcc-a1
tdb: tdb:PbO-98Ris-LB.tdb:FCC_A1

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

PbO-98Ris-LB.tdb: FCC_A1, type code %A, sha256 263b6f32a74f0f62…

49: PHASE FCC_A1 %A 2 1 1 !
50: CONST FCC_A1 : PB% : O VA% : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

GAS (O–Pb)

Id: phase:o-pb:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 930.04–2019.02 K, x(O) 1e-05–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-pb:gas
tdb: tdb:PbO-98Ris-LB.tdb:GAS

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

PbO-98Ris-LB.tdb: GAS, type code %, sha256 263b6f32a74f0f62…

96: PHASE GAS:G % 1 1 !
97: CONST GAS:G : O O2% O3 PB PB2 PBO PB2O2 PB3O3 PB4O4 PB5O5 PB6O6 : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

HCP_A3 (O–Pb)

Id: phase:o-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

Names (2): corpus: corpus:phase:o-pb:hcp-a3
tdb: tdb:PbO-98Ris-LB.tdb:HCP_A3

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

PbO-98Ris-LB.tdb: HCP_A3, type code %A, sha256 263b6f32a74f0f62…

59: PHASE HCP_A3 %A 2 1 0.5 !
60: CONST HCP_A3 : PB : VA : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

ION (O–Pb)

Id: phase:o-pb:ion; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 1162.43–2019.02 K, x(O) 0–0.49856
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-pb:ion
tdb: tdb:PbO-98Ris-LB.tdb:ION

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

PbO-98Ris-LB.tdb: ION, type code %, sha256 263b6f32a74f0f62…

41: PHASE ION:Y % 2 1 1 !
42: CONST ION:Y : PB+2 : O-2 VA : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

LIQUID (O–Pb)

Id: phase:o-pb:liquid; status assigned
Structure: liquid; type st:liquid; liquid; 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

Names (2): corpus: corpus:phase:o-pb:liquid
tdb: tdb:PbO-98Ris-LB.tdb:LIQUID

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

PbO-98Ris-LB.tdb: LIQUID, type code %, sha256 263b6f32a74f0f62…

44: PHASE LIQUID:L % 1 1 !
45: CONST LIQUID:L : PB : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

O2GAS (O–Pb)

Id: phase:o-pb:o2gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 300–315 K, x(O) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-pb:o2gas
tdb: tdb:PbO-98Ris-LB.tdb:O2GAS

TDB models of O2GAS (1): PHASE and CONSTITUENT statements as written

PbO-98Ris-LB.tdb: O2GAS, type code %, sha256 263b6f32a74f0f62…

99: PHASE O2GAS % 1 1 !
100: CONST O2GAS : O2 : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

PB12O17 (O–Pb)

Id: phase:o-pb:pb12o17; status needs_review
No structure assigned. Why: no_structure_token; off_stoichiometric_model; sgte_mmc2_row_incomplete
Candidate (sgte_mmc2): (Pb12O17) · Pmc2_1 (26) — Hallstedt 2025 mmc2 row for PB12O17: Pb12O17
Stability: stable in 1 of 1 calculated diagram(s): 300–325 K, x(O) 0.58621–0.58621
Literature: 13 values (13 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:o-pb:pb12o17
paper: paper:10.1361/105497198770342238:Pb12O17
tdb: tdb:PbO-98Ris-LB.tdb:PB12O17

TDB models of PB12O17 (1): PHASE and CONSTITUENT statements as written

PbO-98Ris-LB.tdb: PB12O17, type code %, sha256 263b6f32a74f0f62…

82: PHASE PB12O17:I % 3 7 5 17 !
83: CONST PB12O17:I : PB+2 : PB+4 : O-2 : !

Example references (3 of 3; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase; reports values for this phase
doi:10.1149/1.2424016 Earl M. Otto, Equilibrium Pressures of Oxygen over Oxides of Lead at Various Temperatures, J. Electrochem. Soc. 113, 525 (1966).
cited as the source of values for this phase
doi:10.1111/j.1151-2916.1964.tb14404.x WILLIAM B. WHITE, RUSTUM ROY, Phase Relations in the System Lead—Oxygen, Journal of the American Ceramic Society 47, 242-249 (1964).
cited as the source of values for this phase

PB12O19 (O–Pb)

Id: phase:o-pb:pb12o19; status assigned
Structure: (Pb12O19) · mP62 · Pc (7); type st:pb12o19-mp62; 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_structure_token, off_stoichiometric_model); structure as stated in the SGTE crystallographic table for this phase name and system
Stability: not stable in 1 calculated diagram(s)
Literature: 18 values (18 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:o-pb:pb12o19
paper: paper:10.1361/105497198770342238:Pb12O19
tdb: tdb:PbO-98Ris-LB.tdb:PB12O19

TDB models of PB12O19 (1): PHASE and CONSTITUENT statements as written

PbO-98Ris-LB.tdb: PB12O19, type code %, sha256 263b6f32a74f0f62…

87: PHASE PB12O19:I % 3 5 7 19 !
88: CONST PB12O19:I : PB+2 : PB+4 : O-2 : !

Example references (5 of 5; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase; reports values for this phase
doi:10.1149/1.2424016 Earl M. Otto, Equilibrium Pressures of Oxygen over Oxides of Lead at Various Temperatures, J. Electrochem. Soc. 113, 525 (1966).
cited as the source of values for this phase
doi:10.1002/bbpc.19120181610 W. Hempel and C. Schubert,"On the Dissociation of Some Oxides, Carbonates, and Sulfides," Z, Elektrochem., 18, 729 (1912) in German.
cited as the source of values for this phase
doi:10.1002/bbpc.19370430108 J. Krustinsons, "On the Termal Decomposition of Lead(4)-Oxides," Z Elektrochem., 40, 246-248 (1934); 43, 65-66 (1937) in German.
cited as the source of values for this phase
doi:10.1111/j.1151-2916.1964.tb14404.x WILLIAM B. WHITE, RUSTUM ROY, Phase Relations in the System Lead—Oxygen, Journal of the American Ceramic Society 47, 242-249 (1964).
cited as the source of values for this phase

PB3O4 (O–Pb)

Id: phase:o-pb:pb3o4; status assigned
Structure: Pb3O4-T · tP28 · P4_2/mbc (135); type st:pb3o4-t-tp28; 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_structure_token, off_stoichiometric_model); structure as stated in the SGTE crystallographic table for this phase name and system
Stability: stable in 1 of 1 calculated diagram(s): 300–307 K, x(O) 0.57143–0.57143
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-pb:pb3o4
tdb: tdb:PbO-98Ris-LB.tdb:PB3O4

TDB models of PB3O4 (1): PHASE and CONSTITUENT statements as written

PbO-98Ris-LB.tdb: PB3O4, type code %, sha256 263b6f32a74f0f62…

77: PHASE PB3O4:I % 3 2 1 4 !
78: CONST PB3O4:I : PB+2 : PB+4 : O-2 : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

PBO_B10 (O–Pb)

Id: phase:o-pb:pbo-b10; status assigned
Structure: PbO-L · B10 · tP4 · P4/nmm (129); type st:b10-pbo-l-tp4; tier A: standard phase name; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 300–515 K, x(O) 0.5–0.5
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-pb:pbo-b10
tdb: tdb:PbO-98Ris-LB.tdb:PBO_B10

TDB models of PBO_B10 (1): PHASE and CONSTITUENT statements as written

PbO-98Ris-LB.tdb: PBO_B10, type code %, sha256 263b6f32a74f0f62…

65: PHASE PBO_B10:I % 2 1 1 !
66: CONST PBO_B10:I : PB+2 : O-2 : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

PBO_M (O–Pb)

Id: phase:o-pb:pbo-m; status assigned
Structure: PbO-M · oP8 · Pbcm (57); type st:pbo-m-op8; 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 (name_has_descriptive_tokens:M, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
Stability: stable in 1 of 1 calculated diagram(s): 930.04–1152.54 K, x(O) 0.5–0.5
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-pb:pbo-m
tdb: tdb:PbO-98Ris-LB.tdb:PBO_M

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

PbO-98Ris-LB.tdb: PBO_M, type code %, sha256 263b6f32a74f0f62…

71: PHASE PBO_M:I % 2 1 1 !
72: CONST PBO_M:I : PB+2 : O-2 : !

Example references (1 of 1; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase

PBO2_C4 (O–Pb)

Id: phase:o-pb:pbo2-c4; status assigned
Structure: TiO2 · C4 · tP6 · P4_2/mnm (136); type st:c4-tio2-tp6; tier A: standard phase name; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 300–325 K, x(O) 0.66667–0.66667
Literature: 10 values (10 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:o-pb:pbo2-c4
paper: paper:10.1361/105497198770342238:PbO2-I.
tdb: tdb:PbO-98Ris-LB.tdb:PBO2_C4

TDB models of PBO2_C4 (1): PHASE and CONSTITUENT statements as written

PbO-98Ris-LB.tdb: PBO2_C4, type code %, sha256 263b6f32a74f0f62…

93: PHASE PBO2_C4:I % 2 1 2 !
94: CONST PBO2_C4:I : PB+4 : O-2 : !

Example references (3 of 3; assessments first):

doi:10.1361/105497198770342238 D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998).
assessment that models this phase; reports values for this phase
doi:10.1016/0021-9614(70)90039-x L. Espada, G. Pilcher, H.A. Skinner, Hot-zone reaction calorimetry II. The enthalpies of formation of lead oxides, The Journal of Chemical Thermodynamics 2, 647-653 (1970).
cited as the source of values for this phase
doi:10.1021/j100848a030 J. A. Duisman, William F. Giauque, Thermodynamics of the lead storage cell. The heat capacity and entropy of lead dioxide from 15 to 318.degree.K, J. Phys. Chem. 72, 562-573 (1968).
cited as the source of values for 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}
}