# O–Pb system

> O–Pb system: 207 accepted literature values (model expression 65, invariant reaction 44, heat capacity / entropy / enthalpy 33, phase transition 32) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

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

207 accepted literature values from 1 paper(s) (experimental 147, model 37, unspecified 23); 0 calculated phase diagram(s). 12 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: [JSON](https://data.orchid-project.org/literature/systems/O-PB.json) · [CSV](https://data.orchid-project.org/systems/O-PB.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#O-PB) · [phases (13)](https://data.orchid-project.org/phases/pages/O-PB.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/O-PB.html) · [Markdown](https://data.orchid-project.org/systems/O-PB.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 147 |
| model | 37 |
| unspecified | 23 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 44 |
| phase transition | 32 |
| formation | 31 |
| heat capacity / entropy / enthalpy | 33 |
| activity / EMF / Gibbs energy | 2 |
| model expression | 65 |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/O/O-PB.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/O/O-PB.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the O–Pb system (44)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 1807 | L = L1 + L2 | L1: Pb 0.704; L2: Pb 0.704 | model | [1] Risold 1998 | Table 8, p. 8, row 17; `ORC-TJD7VUPLWN` |  |
| 1583 | L = L1 + L2 | L1: Pb 0.72; L2: Pb 0.72 | experimental | [1] Risold 1998; _cites Isecke 1977_ | Table 8, p. 8, row 16; `ORC-4SFOQPL5FG` |  |
| 1170 | L2 = L1 + PbO-M | L1: Pb 0.9985 | experimental | [1] Risold 1998; _cites Szware 1972_ | Table 8, p. 8, row 8; `ORC-2KWRGMI7CM` |  |
| 1159 | L2 = L1 + PbO-M | L1: Pb 0.99104 | experimental | [1] Risold 1998; _cites ref. 64Alc_ | Table 8, p. 8, row 7; `ORC-6SYC53QGBF` |  |
| 1159 | L2 + PbO-M + Pb3O4-T | L2: Pb 0.5 | model | [1] Risold 1998 | Table 8, p. 8, row 19; `ORC-OOAC2S26UY` |  |
| 1159 | L2 = L1 + PbO-M | L1: Pb 0.9905 | experimental | [1] Risold 1998; _cites ref. 55Ric_ | Table 8, p. 8, row 6; `ORC-SMSFEUTM4X` |  |
| 1157 | L2 = L1 + PbO-M | L2: Pb 0.501; L1: Pb 0.991 | model | [1] Risold 1998 | Table 8, p. 8, row 15; `ORC-ZZGUAEU2WE` |  |
| 1148 | L2 + PbO-M + Pb3O4-T |  | experimental | [1] Risold 1998; _cites White 1964_ [doi](https://doi.org/10.1111/j.1151-2916.1964.tb14404.x) | Table 8, p. 8, row 18; `ORC-AWGBBTTUQX` |  |
| 1146 | L2 = L1 + PbO-M | L2: Pb 0.501; L1: Pb 0.99485 | experimental | [1] Risold 1998; _cites Kuxmann 1974_ | Table 8, p. 8, row 9; `ORC-NUIVIU5ARL` |  |
| 1145 | L2 = L1 + PbO-M | L1: Pb 0.9916 | experimental | [1] Risold 1998; _cites Taskinen 1979_ | Table 8, p. 8, row 12; `ORC-5UFPGVAFEH` |  |
| 1145 | L2 = L1 + PbO-M | L1: Pb 0.9915 | experimental | [1] Risold 1998; _cites Wriedt 1994_ | Table 8, p. 8, row 14; `ORC-VFONN2R2BK` |  |
| 1143 | L2 = L1 + PbO-M | L2: Pb 0.501; L1: Pb 0.9911 | experimental | [1] Risold 1998; _cites Isecke 1977_ | Table 8, p. 8, row 11; `ORC-HUHR7R6G6I` |  |
| 1143 | L2 = L1 + PbO-M | L1: Pb 0.9911 | experimental | [1] Risold 1998; _cites Charl 1976_ | Table 8, p. 8, row 10; `ORC-KWFZFX77JO` |  |
| 1142 | L2 = L1 + PbO-M |  | experimental | [1] Risold 1998; _cites Ya 1981_ | Table 8, p. 8, row 13; `ORC-OSPPWKJ523` |  |
| 835 | Pb3O4-T = PbO-M + O2 |  | experimental | [1] Risold 1998; _cites M 1976_ | Table 9, p. 12, row 20; `ORC-R42ZKUECH3` |  |
| 820 | Pb3O4-T = PbO-M + O2 |  | experimental | [1] Risold 1998; _cites ref. 1897Lec_ | Table 9, p. 12, row 17; `ORC-532OYHJCL2` |  |
| 810 | Pb3O4-T = PbO-M + O2 |  | experimental | [1] Risold 1998; _cites Reinders 1914_ [doi](https://doi.org/10.1002/zaac.19140890106) | Table 9, p. 12, row 18; `ORC-AQUQU6VSE3` |  |
| 810 | Pb3O4-T = PbO-M + O2 |  | experimental | [1] Risold 1998; _cites Otto 1966_ [doi](https://doi.org/10.1149/1.2424016) | Table 9, p. 12, row 19; `ORC-GMPTE4UITH` |  |
| 808 | Pb3O4-T = PbO-M + O2 |  | experimental | [1] Risold 1998 | Table 9, p. 12, row 22; `ORC-6PTDALNDPM` |  |
| 807 | Pb3O4-T = PbO-M + O2 |  | model | [1] Risold 1998 | Table 9, p. 12, row 23; `ORC-5VJ3ASXFY7` |  |
| 803 | Pb3O4-T = PbO-M + O2 |  | experimental | [1] Risold 1998; _cites Ya 1981_ | Table 9, p. 12, row 21; `ORC-KOFD6CNG6L` |  |
| 662 | Pb12O17 = Pb3O4-T + Pb12O19 |  | model | [1] Risold 1998 | Table 8, p. 8, row 21; `ORC-GN23CWTNB5` |  |
| 653 | Pb12O17 = Pb3O4-T + Pb12O19 |  | experimental | [1] Risold 1998; _cites White 1964_ [doi](https://doi.org/10.1111/j.1151-2916.1964.tb14404.x) | Table 8, p. 8, row 20; `ORC-S4RVYKY4EM` |  |
| 647 | Pb12O17 = Pb3O4-T + O2 |  | experimental | [1] Risold 1998; _cites Buffer 1956_ | Table 9, p. 12, row 13; `ORC-EM6IUVG7LD` |  |
| 638 | Pb12O17 = Pb3O4-T + O2 |  | experimental | [1] Risold 1998; _cites M 1976_ | Table 9, p. 12, row 15; `ORC-J364HWHECG` |  |
| 623 | Pb12O19 = Pb12O17 + O2 |  | experimental | [1] Risold 1998; _cites BystrSm 1946_ | Table 9, p. 12, row 9; `ORC-ZAVCR25SBX` |  |
| 619 | Pb12O17 = Pb3O4-T + O2 |  | experimental | [1] Risold 1998; _cites Otto 1966_ [doi](https://doi.org/10.1149/1.2424016) | Table 9, p. 12, row 14; `ORC-EPJY22EXK2` |  |
| 619 | Pb12O19 = Pb12O17 + O2 |  | experimental | [1] Risold 1998; _cites Otto 1966_ [doi](https://doi.org/10.1149/1.2424016) | Table 9, p. 12, row 11; `ORC-FZMN5RF5ZU` |  |
| 610 | Pb12O17 = Pb3O4-T + O2 |  | model | [1] Risold 1998 | Table 9, p. 12, row 16; `ORC-WKFI7P52GG` |  |
| 600.6 | L1 = Pb + PbO-L | L1: Pb 0.999999 | model | [1] Risold 1998 | Table 8, p. 8, row 5; `ORC-7TVZD4I73H` |  |
| 600 | L1 = Pb + PbO-L | L1: Pb 0.99994 | experimental | [1] Risold 1998; _cites Kuxmann 1974_ | Table 8, p. 8, row 2; `ORC-2P2XCYERSM` |  |
| 600 | L1 = Pb + PbO-L | L1: Pb 1 | experimental | [1] Risold 1998; _cites Reinert 1976_ | Table 8, p. 8, row 3; `ORC-IYTEVE4OXG` |  |
| 600 | L1 = Pb + PbO-L | L1: Pb 0.999999 | experimental | [1] Risold 1998; _cites Wriedt 1994_ | Table 8, p. 8, row 4; `ORC-OGQ24TDJMO` |  |
| 600 | L1 = Pb + PbO-L | L1: Pb 0.999999 | experimental | [1] Risold 1998; _cites ref. 55Ric_ | Table 8, p. 8, row 1; `ORC-SQNZNYGWLC` |  |
| 597 | Pb12O19 = Pb12O17 + O2 |  | experimental | [1] Risold 1998; _cites Buffer 1956_ | Table 9, p. 12, row 10; `ORC-SKZT2I347U` |  |
| 567 | PbO2-I = Pb12O19 + O2 |  | experimental | [1] Risold 1998; _cites Krustinsons 1937_ [doi](https://doi.org/10.1002/bbpc.19370430108) | Table 9, p. 12, row 4; `ORC-YMXQS5GY3I` |  |
| 563 | PbO2-I = Pb12O19 + O2 |  | experimental | [1] Risold 1998; _cites Hempel 1912_ [doi](https://doi.org/10.1002/bbpc.19120181610) | Table 9, p. 12, row 2; `ORC-XWHLHJILYC` |  |
| 553 | PbO2-I = Pb12O19 + O2 |  | experimental | [1] Risold 1998; _cites Carnelley 1888_ | Table 9, p. 12, row 1; `ORC-KRA3GX5Q22` |  |
| 553 | Pb12O19 = Pb12O17 + O2 |  | model | [1] Risold 1998 | Table 9, p. 12, row 12; `ORC-N3ZZXOQSCK` |  |
| 553 | PbO2-I = Pb12O19 + O2 |  | experimental | [1] Risold 1998; _cites Buffer 1956_ | Table 9, p. 12, row 5; `ORC-QXUOAGVMYC` |  |
| 553 | PbO2-I = Pb12O19 + O2 |  | experimental | [1] Risold 1998; _cites ref. 29Mol_ | Table 9, p. 12, row 3; `ORC-RGZ275SKBV` |  |
| 545 | PbO2-I = Pb12O19 + O2 |  | experimental | [1] Risold 1998; _cites M 1976_ | Table 9, p. 12, row 7; `ORC-NYAL5WVYWR` |  |
| 535 | PbO2-I = Pb12O19 + O2 |  | experimental | [1] Risold 1998; _cites Otto 1966_ [doi](https://doi.org/10.1149/1.2424016) | Table 9, p. 12, row 6; `ORC-ANHAA673TI` |  |
| 502 | PbO2-I = Pb12O19 + O2 |  | model | [1] Risold 1998 | Table 9, p. 12, row 8; `ORC-5TII2ACJV7` |  |

## Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from [dft_parity.json](https://data.orchid-project.org/literature/dft_parity.json).

Table: Enthalpies of formation, O–Pb system (13)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| Pb12O17 |  | -104.58 kJ/mol-atom | 298.15 | model |  |  | [1] Risold 1998 | Table 1, p. 1, row 17; `ORC-T6L73NMWAY.13d2d0` |  |
| Pb12O19 |  | -100.368 kJ/mol-atom | 298.15 | model |  |  | [1] Risold 1998 | Table 1, p. 1, row 18; `ORC-GBISJLEMBL.0f5ba0` |  |
| Pb3O4-T | [Pb3O4](https://data.orchid-project.org/compounds/Pb3O4.html) | -104.839 kJ/mol-atom | 298.15 | model | -139.612 (mp-aaaabhmn) | -123.983 (oqmd-669607) | [1] Risold 1998 | Table 1, p. 1, row 14; `ORC-Y2WSRB4DLG.15a3c1` |  |
| Pb3O4-T | [Pb3O4](https://data.orchid-project.org/compounds/Pb3O4.html) | -102.669 kJ/mol-atom | 298.15 | experimental | -139.612 (mp-aaaabhmn) | -123.983 (oqmd-669607) | [1] Risold 1998; _cites Espada 1970_ [doi](https://doi.org/10.1016/0021-9614%2870%2990039-x) | Table 1, p. 1, row 12; `ORC-OMX5IAEZKZ.9bd070` |  |
| Pb3O4-T | [Pb3O4](https://data.orchid-project.org/compounds/Pb3O4.html) | -102.669 kJ/mol-atom | 298.15 | unspecified | -139.612 (mp-aaaabhmn) | -123.983 (oqmd-669607) | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 13; `ORC-Y6RXZK3NHU.44ced2` |  |
| PbO-L | [PbO](https://data.orchid-project.org/compounds/PbO.html) | -109.704 kJ/mol-atom | 298.15 | unspecified | -141.744 (mp-aaabmglh) | -128.56 (oqmd-2074732) | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 1; `ORC-WJSD3QZ4PX.45c8da` |  |
| PbO-L | [PbO](https://data.orchid-project.org/compounds/PbO.html) | -109.528 kJ/mol-atom | 298.15 | model | -141.744 (mp-aaabmglh) | -128.56 (oqmd-2074732) | [1] Risold 1998 | Table 1, p. 1, row 2; `ORC-2NEHG54LHP.72b531` |  |
| PbO-M | [PbO](https://data.orchid-project.org/compounds/PbO.html) | -109.031 kJ/mol-atom | 298.15 | experimental | -141.744 (mp-aaabmglh) | -128.56 (oqmd-2074732) | [1] Risold 1998; _cites Espada 1970_ [doi](https://doi.org/10.1016/0021-9614%2870%2990039-x) | Table 1, p. 1, row 6; `ORC-DV5UE3EBHF.3a34d8` |  |
| PbO-M | [PbO](https://data.orchid-project.org/compounds/PbO.html) | -109.031 kJ/mol-atom | 298.15 | unspecified | -141.744 (mp-aaabmglh) | -128.56 (oqmd-2074732) | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 7; `ORC-YPJWHM6ZHU.3e52c7` |  |
| PbO-M | [PbO](https://data.orchid-project.org/compounds/PbO.html) | -108.721 kJ/mol-atom | 298.15 | model | -141.744 (mp-aaabmglh) | -128.56 (oqmd-2074732) | [1] Risold 1998 | Table 1, p. 1, row 8; `ORC-XYFQXGYQGO.9e2ed3` |  |
| PbO2-I. | [PbO2](https://data.orchid-project.org/compounds/PbO2.html) | -93.9067 kJ/mol-atom | 298.15 | model | -125.396 (mp-aaaaberd) | -107.539 (oqmd-4264) | [1] Risold 1998 | Table 1, p. 1, row 22; `ORC-CLUULVACZM.4a06e2` |  |
| PbO2-I. | [PbO2](https://data.orchid-project.org/compounds/PbO2.html) | -91.504 kJ/mol-atom | 298.15 | experimental | -125.396 (mp-aaaaberd) | -107.539 (oqmd-4264) | [1] Risold 1998; _cites Espada 1970_ [doi](https://doi.org/10.1016/0021-9614%2870%2990039-x) | Table 1, p. 1, row 20; `ORC-TGORSEP3OM.218b0c` |  |
| PbO2-I. | [PbO2](https://data.orchid-project.org/compounds/PbO2.html) | -91.49 kJ/mol-atom | 298.15 | unspecified | -125.396 (mp-aaaaberd) | -107.539 (oqmd-4264) | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 21; `ORC-XBKUWNAOEM.2feedc` |  |

## Other properties

### Phase transition (32)

Table: Phase transition, O–Pb system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase transition | 423 K | 423 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites Le 1940_ | Table 2, p. 3, row 6; `ORC-PBQKVALFVC` |  |
| Phase transition | 760.5 K | 760.5 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites ref. 46Kam_ | Table 2, p. 3, row 9; `ORC-XPFXSB3SXC` |  |
| Phase transition | 761 K | 761 | polymorphic: PbO-L \<-> PbO-M | unspecified | [1] Risold 1998; _cites ref. 46Pam_ | Table 2, p. 3, row 10; `ORC-4445LXWCMN` |  |
| Phase transition | 762 K | 762 | polymorphic: PbO-L \<-> PbO-M | model | [1] Risold 1998 | Table 2, p. 3, row 16; `ORC-J472Z632GQ` |  |
| Phase transition | 762 K | 762 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites Cohen 1934_ [doi](https://doi.org/10.1515/zpch-1934-16813) | Table 2, p. 3, row 4; `ORC-LHBGT63OEY` |  |
| Phase transition | 762 K | 762 | polymorphic: PbO-L \<-> PbO-M | model | [1] Risold 1998; _cites Chase 1985_ | Table 2, p. 3, row 14; `ORC-WWDIT4HNXZ` |  |
| Phase transition | 763 K | 763 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites Coussaert 1968_ | Table 2, p. 3, row 12; `ORC-4NUDISKVXK` |  |
| Phase transition | 763 K | 763 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites Peterson 1941_ | Table 2, p. 3, row 8; `ORC-A75U4IAVCR` |  |
| Phase transition | 803 K | 803 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites ref. 36Ren1_ | Table 2, p. 3, row 5; `ORC-UTB7JEHQVI` |  |
| Phase transition | 813 K | 813 | polymorphic: PbO-L \<-> PbO-M | model | [1] Risold 1998; _cites Wriedt 1994_ | Table 2, p. 3, row 15; `ORC-LBIKMAEXIG` |  |
| Phase transition | 813.5 K | 813.5 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites Rooymans 1968_ [doi](https://doi.org/10.1016/0022-0248%2868%2990187-5) | Table 2, p. 3, row 13; `ORC-B7IFFWH7EK` |  |
| Phase transition | 816 K | 816 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites White 1961_ | Table 2, p. 3, row 11; `ORC-TMF4QHZDT6` |  |
| Phase transition | 823 K | 823 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites Le 1940_ | Table 2, p. 3, row 7; `ORC-NLCKFAM4SN` |  |
| Phase transition | 853 K | 853 | polymorphic: PbO-L \<-> PbO-M | unspecified | [1] Risold 1998; _cites ref. 1897Lec_ | Table 2, p. 3, row 1; `ORC-O2BHLGEWEL` |  |
| Phase transition | 860 K | 860 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites EM 1921_ | Table 2, p. 3, row 3; `ORC-ITVIFR2YOK` |  |
| Phase transition | 893 K | 893 | polymorphic: PbO-L \<-> PbO-M | experimental | [1] Risold 1998; _cites Ruer 1906_ [doi](https://doi.org/10.1002/zaac.19060500125) | Table 2, p. 3, row 2; `ORC-NZUKSKH246` |  |
| Phase transition | 1103 K | 1103 | congruent transformation: \[1897Lec\] | unspecified | [1] Risold 1998; _cites ref. 1897Lec_ | Table 5, p. 5, row 1; `ORC-JQXXBJMISV` |  |
| Phase transition | 1143 K | 1143 | congruent transformation: \[22Bel\] | experimental | [1] Risold 1998; _cites Belladen 1922_ | Table 5, p. 5, row 7; `ORC-5XS3I25BL7` |  |
| Phase transition | 1143 K | 1143 | congruent transformation: \[81Kha\] | unspecified | [1] Risold 1998; _cites Ya 1981_ | Table 5, p. 5, row 15; `ORC-TBM242YWNL` |  |
| Phase transition | 1149 K | 1149 | congruent transformation: \[09Hil\] | unspecified | [1] Risold 1998; _cites ref. 09Hil_ | Table 5, p. 5, row 4; `ORC-GBF4QHBKRH` |  |
| Phase transition | 1151 K | 1151 | congruent transformation: \[21Jae\] | experimental | [1] Risold 1998; _cites EM 1921_ | Table 5, p. 5, row 6; `ORC-PJLSXUXI66` |  |
| Phase transition | 1152 K | 1152 | congruent transformation: \[08Sch\] | unspecified | [1] Risold 1998; _cites ref. 08Sch_ | Table 5, p. 5, row 2; `ORC-SJCZ5GD6XK` |  |
| Phase transition | 1157 K | 1157 | congruent transformation: \[34Coh\] | experimental | [1] Risold 1998; _cites Cohen 1934_ [doi](https://doi.org/10.1515/zpch-1934-16813) | Table 5, p. 5, row 8; `ORC-4M5YJBIEKA` |  |
| Phase transition | 1158 K | 1158 | congruent transformation: \[64Kna\] | experimental | [1] Risold 1998; _cites Knacke 1964_ | Table 5, p. 5, row 14; `ORC-G7XOXGXCQ5` |  |
| Phase transition | 1159 K | 1159 | congruent transformation: This work | model | [1] Risold 1998 | Table 5, p. 5, row 16; `ORC-77PSITQHMZ` |  |
| Phase transition | 1159 K | 1159 | congruent transformation: \[34Gel\] | experimental | [1] Risold 1998; _cites R 1934_ | Table 5, p. 5, row 9; `ORC-LB4FSJIP25` |  |
| Phase transition | 1159 K | 1159 | congruent transformation: \[36Kra\] | unspecified | [1] Risold 1998; _cites ref. 36Kra_ | Table 5, p. 5, row 10; `ORC-C4N4Q5WD2R` |  |
| Phase transition | 1159 K | 1159 | congruent transformation: \[39Leb\] | experimental | [1] Risold 1998; _cites Le 1940_ | Table 5, p. 5, row 11; `ORC-W5CDPLCXKT` |  |
| Phase transition | 1159 K | 1159 | congruent transformation: \[63Sch\] | model | [1] Risold 1998; _cites Schneider 1964_ | Table 5, p. 5, row 13; `ORC-VJHF642KAI` |  |
| Phase transition | 1161 K | 1161 | congruent transformation: \[09Coo\] | unspecified | [1] Risold 1998; _cites ref. 09Coo_ | Table 5, p. 5, row 3; `ORC-7PL43ZKQEG` |  |
| Phase transition | 1161 K | 1161 | congruent transformation: \[12Kro\] | experimental | [1] Risold 1998; _cites Kroll 1912_ [doi](https://doi.org/10.1002/zaac.19120780107) | Table 5, p. 5, row 5; `ORC-43EJQOIEKQ` |  |
| Phase transition | 1170 K | 1170 | congruent transformation: \[61Rod\] | experimental | [1] Risold 1998; _cites Rodigina 1961_ | Table 5, p. 5, row 12; `ORC-VAX2K37QO6` |  |

### Formation (18)

Table: Formation, O–Pb system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Entropy of formation; _printed: ΔS (transformation)_ | 2.39 J/mol (basis unstated)/K | 298.15 | PbO; _alloy: Pb 0.5_ | model | [1] Risold 1998 | Table 3, p. 3, row 3; `ORC-T44PFMHWIK.4b9fb9` |  |
| Entropy of formation; _printed: ΔS (transformation)_ | 1.35 J/mol (basis unstated)/K | 762 | PbO; _alloy: Pb 0.5_ | model | [1] Risold 1998 | Table 3, p. 3, row 4; `ORC-CUWLAZZ6ON.36966e` |  |
| Entropy of formation; _printed: ΔS (transformation)_ | 0.79 J/mol (basis unstated)/K | 816 | PbO; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites White 1961_ | Table 3, p. 3, row 5; `ORC-RAROPLC3YN.75240a` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -86.5045 kJ/mol-atom | 298.15 | Pb12O17; _alloy: Pb 0.413793_ | model | [1] Risold 1998 | Table 1, p. 1, row 17; `ORC-T6L73NMWAY.954211` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -82.3885 kJ/mol-atom | 298.15 | Pb12O19; _alloy: Pb 0.387097_ | model | [1] Risold 1998 | Table 1, p. 1, row 25; `ORC-DQCJLROPIQ` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -81.74 kJ/mol-atom | 298.15 | Pb12O19; _alloy: Pb 0.387097_ | experimental | [1] Risold 1998; _cites E Chattier 1963_ | Table 1, p. 1, row 19; `ORC-GSPOWJBXIK.0d6e4f` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -88.17 kJ/mol-atom | 298.15 | Pb3O4-T; _alloy: Pb 0.428571_ | experimental | [1] Risold 1998; _cites E Chattier 1963_ | Table 1, p. 1, row 16; `ORC-H6CAMZNZB6.9934b5` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -85.3297 kJ/mol-atom | 298.15 | Pb3O4-T; _alloy: Pb 0.428571_ | experimental | [1] Risold 1998; _cites Andrews 1934_ [doi](https://doi.org/10.1021/ja01317a032) | Table 1, p. 1, row 15; `ORC-SRQYCLOPWT.a90ea0` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -87.8996 kJ/mol-atom | 298.15 | Pb3O4-T; _alloy: Pb 0.428571_ | model | [1] Risold 1998 | Table 1, p. 1, row 14; `ORC-Y2WSRB4DLG.ca1e8f` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -85.9437 kJ/mol-atom | 298.15 | Pb3O4-T; _alloy: Pb 0.428571_ | unspecified | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 13; `ORC-Y6RXZK3NHU.83b608` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -94.4685 kJ/mol-atom | 298.15 | PbO-L; _alloy: Pb 0.5_ | model | [1] Risold 1998 | Table 1, p. 1, row 2; `ORC-2NEHG54LHP.d715d7` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -94.5205 kJ/mol-atom | 298.15 | PbO-L; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites D 1923_ | Table 1, p. 1, row 3; `ORC-GHCN4AU6KY.0f4f25` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -94.6415 kJ/mol-atom | 298.15 | PbO-L; _alloy: Pb 0.5_ | unspecified | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 1; `ORC-WJSD3QZ4PX.2c03e5` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -94.018 kJ/mol-atom | 298.15 | PbO-M; _alloy: Pb 0.5_ | model | [1] Risold 1998 | Table 1, p. 1, row 8; `ORC-XYFQXGYQGO.cc9039` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -94.3235 kJ/mol-atom | 298.15 | PbO-M; _alloy: Pb 0.5_ | unspecified | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 7; `ORC-YPJWHM6ZHU.172eec` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -74.2247 kJ/mol-atom | 298.15 | PbO2-I.; _alloy: Pb 0.333333_ | model | [1] Risold 1998 | Table 1, p. 1, row 22; `ORC-CLUULVACZM.8d65ee` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -72.983 kJ/mol-atom | 298.15 | PbO2-I.; _alloy: Pb 0.333333_ | unspecified | [1] Risold 1998; _cites ref. 29Mil_ | Table 1, p. 1, row 23; `ORC-EEZPHU7IHB.321212` |  |
| Gibbs energy of formation; _printed: ΔfG298_ | -71.799 kJ/mol-atom | 298.15 | PbO2-I.; _alloy: Pb 0.333333_ | unspecified | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 21; `ORC-XBKUWNAOEM.2a4caf` |  |

### Heat capacity / entropy / enthalpy (33)

Table: Heat capacity / entropy / enthalpy, O–Pb system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Entropy; _printed: ΔS_ | 21.2 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charette 1968_ [doi](https://doi.org/10.1149/1.2411434) | Table 6, p. 5, row 6; `ORC-4NH7VN6F22.4753ae` |  |
| Entropy; _printed: ΔS_ | 23.6 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 64Mat1_ | Table 6, p. 5, row 5; `ORC-7NOF4LASPF.80c70b` |  |
| Entropy; _printed: ΔS_ | 21.9 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Rodigina 1961_ | Table 6, p. 5, row 3; `ORC-B45LUILISO.51b479` |  |
| Entropy; _printed: ΔS_ | 24.9 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1975_ | Table 6, p. 5, row 13; `ORC-E33QZC6IKY.3805c4` |  |
| Entropy; _printed: ΔS_ | 24.7 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1973_ [doi](https://doi.org/10.1016/0036-9748%2873%2990012-4) | Table 6, p. 5, row 10; `ORC-EXSY5A4DC5.235408` |  |
| Entropy; _printed: ΔS_ | 26.4 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Iwase 1975_ [doi](https://doi.org/10.2320/jinstmet1952.39.11_1118) | Table 6, p. 5, row 12; `ORC-GHZY3JAHKD.c44b0b` |  |
| Entropy; _printed: ΔS_ | 22.2 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Taskinen 1979_ | Table 6, p. 5, row 15; `ORC-KTVHLROLEW.1c4a9a` |  |
| Entropy; _printed: ΔS_ | 24.5 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charl 1976_ | Table 6, p. 5, row 14; `ORC-MLLJ3IOJOS.a0fa19` |  |
| Entropy; _printed: ΔS_ | 25.1 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 55Ric_ | Table 6, p. 5, row 2; `ORC-MQC7B4OWDN.8e4e5f` |  |
| Entropy; _printed: ΔS_ | 21.3 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Szware 1972_ | Table 6, p. 5, row 9; `ORC-SQBE2BCVQG.5ac2b6` |  |
| Entropy; _printed: ΔS_ | 24.3 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 75Cal_ | Table 6, p. 5, row 11; `ORC-TN7CTSM6H4.c8f2f7` |  |
| Entropy; _printed: ΔS_ | 24 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ICT 1971_ | Table 6, p. 5, row 7; `ORC-TRCPTRZ2OI.e2afed` |  |
| Entropy; _printed: ΔS_ | 22.9 J/mol·K |  | PbO-M; _alloy: Pb 0.5_ | model | [1] Risold 1998 | Table 6, p. 5, row 16; `ORC-WCIZIQ7RTN.5d1234` |  |
| Entropy; _printed: S_ | 76.4 J/mol 9K | 298.15 |  | experimental | [1] Risold 1998; _cites ref. 29Mil_ | p. 12; `ORC-GFKCNZ5MZQ.787df6` | “The data of \[29Mil\] led to the value of 76.4 J/mol 9K for the entropy at 298 K, whereas \[68Dui\] obtained the value 71.8 J/mol. K.” |
| Entropy; _printed: S_ | 71.8 J/mol. K | 298.15 |  | experimental | [1] Risold 1998; _cites Duisman 1968_ [doi](https://doi.org/10.1021/j100848a030) | p. 12; `ORC-GFKCNZ5MZQ.b9ac93` | “The data of \[29Mil\] led to the value of 76.4 J/mol 9K for the entropy at 298 K, whereas \[68Dui\] obtained the value 71.8 J/mol. K.” |
| Entropy; _printed: S298_ | 27.2759 J/mol-atom/K | 298.15 | Pb12O17; _alloy: Pb 0.413793_ | model | [1] Risold 1998 | Table 1, p. 1, row 17; `ORC-T6L73NMWAY.96b512` |  |
| Entropy; _printed: S298_ | 27.6129 J/mol-atom/K | 298.15 | Pb12O19; _alloy: Pb 0.387097_ | model | [1] Risold 1998 | Table 1, p. 1, row 18; `ORC-GBISJLEMBL.06b0c2` |  |
| Entropy; _printed: S298_ | 29.5714 J/mol-atom/K | 298.15 | Pb3O4-T; _alloy: Pb 0.428571_ | model | [1] Risold 1998 | Table 1, p. 1, row 14; `ORC-Y2WSRB4DLG.7e51f5` |  |
| Entropy; _printed: S298_ | 30.2857 J/mol-atom/K | 298.15 | Pb3O4-T; _alloy: Pb 0.428571_ | unspecified | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 13; `ORC-Y6RXZK3NHU.bfbd6c` |  |
| Entropy; _printed: S298_ | 33.15 J/mol-atom/K | 298.15 | PbO-L; _alloy: Pb 0.5_ | model | [1] Risold 1998 | Table 1, p. 1, row 2; `ORC-2NEHG54LHP.180250` |  |
| Entropy; _printed: S298_ | 32.65 J/mol-atom/K | 298.15 | PbO-L; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites King 1958_ [doi](https://doi.org/10.1021/ja01543a014) | Table 1, p. 1, row 5; `ORC-AC5XP45GUD.931f48` |  |
| Entropy; _printed: S298_ | 33.15 J/mol-atom/K | 298.15 | PbO-L; _alloy: Pb 0.5_ | unspecified | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 1; `ORC-WJSD3QZ4PX.dacb82` |  |
| Entropy; _printed: ΔS_ | 2.39 J/mol · K | 298.15 | PbO-L + PbO-M | model | [1] Risold 1998 | Table 3, p. 3, row 3; `ORC-T44PFMHWIK.072ffe` |  |
| Entropy; _printed: S298_ | 34.35 J/mol-atom/K | 298.15 | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Kostryukov 1960_ | Table 1, p. 1, row 11; `ORC-EJXJD4ZJTD.186c36` |  |
| Entropy; _printed: S298_ | 33.7 J/mol-atom/K | 298.15 | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites King 1958_ [doi](https://doi.org/10.1021/ja01543a014) | Table 1, p. 1, row 10; `ORC-QVWYFNMTFW.25576d` |  |
| Entropy; _printed: S298_ | 34.35 J/mol-atom/K | 298.15 | PbO-M; _alloy: Pb 0.5_ | model | [1] Risold 1998 | Table 1, p. 1, row 8; `ORC-XYFQXGYQGO.a16b2a` |  |
| Entropy; _printed: S298_ | 34.35 J/mol-atom/K | 298.15 | PbO-M; _alloy: Pb 0.5_ | unspecified | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 7; `ORC-YPJWHM6ZHU.fed808` |  |
| Entropy; _printed: S298_ | 23.9333 J/mol-atom/K | 298.15 | PbO2-I.; _alloy: Pb 0.333333_ | model | [1] Risold 1998 | Table 1, p. 1, row 22; `ORC-CLUULVACZM.85e916` |  |
| Entropy; _printed: S298_ | 23.9333 J/mol-atom/K | 298.15 | PbO2-I.; _alloy: Pb 0.333333_ | experimental | [1] Risold 1998; _cites Duisman 1968_ [doi](https://doi.org/10.1021/j100848a030) | Table 1, p. 1, row 24; `ORC-CZYMM2JLMK.6d7ee3` |  |
| Entropy; _printed: S298_ | 25.4667 J/mol-atom/K | 298.15 | PbO2-I.; _alloy: Pb 0.333333_ | unspecified | [1] Risold 1998; _cites ref. 29Mil_ | Table 1, p. 1, row 23; `ORC-EEZPHU7IHB.bf7c90` |  |
| Entropy; _printed: S298_ | 23.9333 J/mol-atom/K | 298.15 | PbO2-I.; _alloy: Pb 0.333333_ | unspecified | [1] Risold 1998; _cites Chase 1985_ | Table 1, p. 1, row 21; `ORC-XBKUWNAOEM.c3910c` |  |
| Entropy; _printed: ΔS_ | 1.35 J/mol · K | 762 | PbO-L + PbO-M | model | [1] Risold 1998 | Table 3, p. 3, row 4; `ORC-CUWLAZZ6ON.832cda` |  |
| Entropy; _printed: ΔS_ | 0.79 J/mol · K | 816 | PbO-L + PbO-M | experimental | [1] Risold 1998; _cites White 1961_ | Table 3, p. 3, row 5; `ORC-RAROPLC3YN.331b5b` |  |

### Activity / EMF / Gibbs energy (2)

Table: Activity / EMF / Gibbs energy, O–Pb system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Vapour pressure; _printed: p(O2)_ | 0.59 bar 02 | 515 |  | experimental | [1] Risold 1998 | p. 13; `ORC-HV7J6ATSWX` | “This evolution of oxygen was so slow that a precise value for the equilibrium oxygen pressure could not be obtained; however, it gives a limiting interval of 0.59 to 1.19 bar 02 at 515 K.” |
| Vapour pressure; _printed: p(O2)_ | 2 bar | 653 | Pb3Oa-T + Pb12017 + Pb\]2019 | experimental | [1] Risold 1998; _cites White 1964_ | p. 12; `ORC-ZSJFSYRUEL` | “The three phase Pb3Oa-T, Pb12017, and Pb\]2019 have been predicted to be in equilibrium at about 653 K and 2 bar 02 based on the XRD analysis of annealed samples \[64Whi, 65Roy\].” |

### Model expression (65)

Table: Model expression, O–Pb system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| gibbs energy expression term; _printed: ΔG0 constant term_ | -189851 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Taskinen 1979_ | Table 7, p. 6, row 38; `ORC-6JENYV5NM4.72d047` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 74.36 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Taskinen 1979_ | Table 7, p. 6, row 38; `ORC-6JENYV5NM4.932bc1` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -191753 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Sridhar 1967_ | Table 7, p. 6, row 22; `ORC-7SRELQNYZO` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -188615 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charl 1976_ | Table 7, p. 6, row 33; `ORC-B6YVTDHZ2O` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -191350 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Sugawara 1977_ [doi](https://doi.org/10.1007/bf02696940) | Table 7, p. 6, row 37; `ORC-BKOUCOUWOQ.463019` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 74.6 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Sugawara 1977_ [doi](https://doi.org/10.1007/bf02696940) | Table 7, p. 6, row 37; `ORC-BKOUCOUWOQ.892501` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 74.91 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ICT 1971_ | Table 7, p. 6, row 24; `ORC-CAXLFA76XZ.0557d5` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -191008 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ICT 1971_ | Table 7, p. 6, row 24; `ORC-CAXLFA76XZ.0686b1` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -191209 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Kapoor 1973_ [doi](https://doi.org/10.1179/cmq.1973.12.2.137) | Table 7, p. 6, row 28; `ORC-FDMTHP3D4Q.0e7ddf` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 73.64 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Kapoor 1973_ [doi](https://doi.org/10.1179/cmq.1973.12.2.137) | Table 7, p. 6, row 28; `ORC-FDMTHP3D4Q.89c56f` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -180761 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Kapoor 1971_ [doi](https://doi.org/10.1080/00305316.1971.10434031) | Table 7, p. 6, row 25; `ORC-G2USQ5HTNL.93dbe7` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 65.44 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Kapoor 1971_ [doi](https://doi.org/10.1080/00305316.1971.10434031) | Table 7, p. 6, row 25; `ORC-G2USQ5HTNL.e5e9c5` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 79.89 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Minenko 1963_ | Table 7, p. 6, row 20; `ORC-I3FO263E6Z.3cc329` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -191093 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Minenko 1963_ | Table 7, p. 6, row 20; `ORC-I3FO263E6Z.3f4ada` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 94.14 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Perrot 1976_ | Table 7, p. 6, row 35; `ORC-JCQ45TXHIZ.6746c4` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -214430 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Perrot 1976_ | Table 7, p. 6, row 35; `ORC-JCQ45TXHIZ.ec0e54` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 71.38 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 75Cal_ | Table 7, p. 6, row 30; `ORC-KYEOEL7CKE.2bdc7b` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -185891 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 75Cal_ | Table 7, p. 6, row 30; `ORC-KYEOEL7CKE.ee05d0` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -190623 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Szware 1972_ | Table 7, p. 6, row 27; `ORC-MR3BS3Q4M7` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -184700 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Iwase 1975_ [doi](https://doi.org/10.2320/jinstmet1952.39.11_1118) | Table 7, p. 6, row 31; `ORC-OFGUGQTWUW.9b54e1` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 70.92 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Iwase 1975_ [doi](https://doi.org/10.2320/jinstmet1952.39.11_1118) | Table 7, p. 6, row 31; `ORC-OFGUGQTWUW.f2f98b` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -214430 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Codron 1972_ | Table 7, p. 6, row 26; `ORC-QKKZCF7ATX.3b58a4` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 91.14 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Codron 1972_ | Table 7, p. 6, row 26; `ORC-QKKZCF7ATX.f7837d` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 69.45 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1973_ [doi](https://doi.org/10.1016/0036-9748%2873%2990012-4) | Table 7, p. 6, row 29; `ORC-RJ4Y7ATZDE.b7c67b` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -185226 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1973_ [doi](https://doi.org/10.1016/0036-9748%2873%2990012-4) | Table 7, p. 6, row 29; `ORC-RJ4Y7ATZDE.ec7964` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 75.15 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charette 1968_ [doi](https://doi.org/10.1149/1.2411434) | Table 7, p. 6, row 23; `ORC-S7FJWUCXT5.72a067` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -190623 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charette 1968_ [doi](https://doi.org/10.1149/1.2411434) | Table 7, p. 6, row 23; `ORC-S7FJWUCXT5.c3c71b` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 81.3 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Suito 1976_ [doi](https://doi.org/10.2320/matertrans1960.17.819) | Table 7, p. 6, row 36; `ORC-U3XUDFW34N.654c11` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -194472 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Suito 1976_ [doi](https://doi.org/10.2320/matertrans1960.17.819) | Table 7, p. 6, row 36; `ORC-U3XUDFW34N.9c122e` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 74.56 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 64Mat1_ | Table 7, p. 6, row 21; `ORC-X5TFHMYIWT.8a3587` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -191229 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 64Mat1_ | Table 7, p. 6, row 21; `ORC-X5TFHMYIWT.f4a4ad` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -189410 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1975_ | Table 7, p. 6, row 32; `ORC-XAIFWDJOFR.081018` |  |
| gibbs energy expression term; _printed: ΔG0 coefficient of T_ | 72.63 J/mol/K |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1975_ | Table 7, p. 6, row 32; `ORC-XAIFWDJOFR.ef3168` |  |
| gibbs energy expression term; _printed: ΔG0 constant term_ | -189037 J/mol |  | PbO(liq); _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Leung 1976_ [doi](https://doi.org/10.1179/cmq.1976.15.3.227) | Table 7, p. 6, row 34; `ORC-XCRL2B5SLN` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 95.65 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 75Cal_ | Table 4, p. 4, row 21; `ORC-3KEZUDCW43.124339` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -214660 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 75Cal_ | Table 4, p. 4, row 21; `ORC-3KEZUDCW43.f449ce` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -218279 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1975_ | Table 4, p. 4, row 23; `ORC-45TNHIY2CV.0adfe8` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 97.49 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1975_ | Table 4, p. 4, row 23; `ORC-45TNHIY2CV.76d62a` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 97.4 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Sugimoto 1980_ [doi](https://doi.org/10.2320/jinstmet1952.44.6_644) | Table 4, p. 4, row 26; `ORC-5DGXFVL2W6.870951` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -216000 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Sugimoto 1980_ [doi](https://doi.org/10.2320/jinstmet1952.44.6_644) | Table 4, p. 4, row 26; `ORC-5DGXFVL2W6.db75c8` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -220010 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 84Ban_ | Table 4, p. 4, row 27; `ORC-7WY7KD3DQA.554ef4` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 100.91 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 84Ban_ | Table 4, p. 4, row 27; `ORC-7WY7KD3DQA.ba08cc` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -218099 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ICT 1971_ | Table 4, p. 4, row 18; `ORC-FT7FRB74NH.73bae1` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 98.89 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ICT 1971_ | Table 4, p. 4, row 18; `ORC-FT7FRB74NH.e4c58a` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 92.54 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mallika 1995_ | Table 4, p. 4, row 28; `ORC-GMY4XJ34JG.549d09` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -212640 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mallika 1995_ | Table 4, p. 4, row 28; `ORC-GMY4XJ34JG.c28a5e` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 96.39 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charette 1968_ [doi](https://doi.org/10.1149/1.2411434) | Table 4, p. 4, row 17; `ORC-GQFCYEYJV5.5c7230` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -215058 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charette 1968_ [doi](https://doi.org/10.1149/1.2411434) | Table 4, p. 4, row 17; `ORC-GQFCYEYJV5.c458ca` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -215231 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Taskinen 1979_ | Table 4, p. 4, row 25; `ORC-HWYBORPRBG.720909` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 96.54 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Taskinen 1979_ | Table 4, p. 4, row 25; `ORC-HWYBORPRBG.7cd3a5` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -219367 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 64Alc_ | Table 4, p. 4, row 15; `ORC-IGSS4VJVDZ.9d22a0` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 100.92 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 64Alc_ | Table 4, p. 4, row 15; `ORC-IGSS4VJVDZ.eccd18` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 97.28 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Iwase 1975_ [doi](https://doi.org/10.2320/jinstmet1952.39.11_1118) | Table 4, p. 4, row 22; `ORC-M2OQMZXN24.0d5918` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -215000 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Iwase 1975_ [doi](https://doi.org/10.2320/jinstmet1952.39.11_1118) | Table 4, p. 4, row 22; `ORC-M2OQMZXN24.54259e` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -215058 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Szware 1972_ | Table 4, p. 4, row 19; `ORC-Q6R43IXJHI.5fab91` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 96.23 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Szware 1972_ | Table 4, p. 4, row 19; `ORC-Q6R43IXJHI.c48494` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 98.03 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charl 1976_ | Table 4, p. 4, row 24; `ORC-RB5SGMXE2K.ea7d76` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -216606 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Charl 1976_ | Table 4, p. 4, row 24; `ORC-RB5SGMXE2K.eef970` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 94.14 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1973_ [doi](https://doi.org/10.1016/0036-9748%2873%2990012-4) | Table 4, p. 4, row 20; `ORC-T5EZPWHW3M.6b89f9` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -214095 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Mehrotra 1973_ [doi](https://doi.org/10.1016/0036-9748%2873%2990012-4) | Table 4, p. 4, row 20; `ORC-T5EZPWHW3M.f91a9f` |  |
| gibbs energy expression term; _printed: ΔG0 (constant term)_ | -218059 J/mol |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 64Mat1_ | Table 4, p. 4, row 16; `ORC-Y2NEVWGGZX.236a32` |  |
| gibbs energy expression term; _printed: ΔG0 (T coefficient)_ | 98.2 J/mol/K |  | UNKNOWN; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites ref. 64Mat1_ | Table 4, p. 4, row 16; `ORC-Y2NEVWGGZX.b54ebb` |  |
| gm form expression term; _printed: ΔfG298 (a)_ | -94.659 kJ/mol-atom |  | PbO-L; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Spencer 1932_ [doi](https://doi.org/10.1021/ja01351a018) | Table 1, p. 1, row 4; `ORC-RQM5UTYKXI.4dfee6` |  |
| gm form expression term; _printed: ΔfG298 (a)_ | -94.3555 kJ/mol-atom |  | PbO-M; _alloy: Pb 0.5_ | experimental | [1] Risold 1998; _cites Spencer 1932_ [doi](https://doi.org/10.1021/ja01351a018) | Table 1, p. 1, row 9; `ORC-FTEQRLKT76.6d8dd4` |  |
| gm form expression term; _printed: ΔfG298 (a)_ | -72.983 kJ/mol-atom |  | PbO2-I; _alloy: Pb 0.333333_ | unspecified | [1] Risold 1998; _cites ref. 29Mil_ | Table 1, p. 1, row 23; `ORC-EEZPHU7IHB.a28455` |  |

## Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

1. D. Risold, J. -I. Nagata, R. O. Suzuki, Thermodynamic description of the Pb-O system, JPE 19, 213-233 (1998). [doi:10.1361/105497198770342238](https://doi.org/10.1361/105497198770342238)

## Please cite

- R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735569
- R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). https://doi.org/10.5281/zenodo.23735891
- 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 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); 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.

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_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@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/).