# Ca–Fe–O system

> Ca–Fe–O system: 72 accepted literature values (invariant reaction 61, heat capacity / entropy / enthalpy 8, activity / EMF / Gibbs energy 2, phase transition 1) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

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

72 accepted literature values from 1 paper(s) (experimental 33, model 39); 0 calculated phase diagram(s).

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

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 33 |
| model | 39 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 61 |
| phase transition | 1 |
| heat capacity / entropy / enthalpy | 8 |
| activity / EMF / Gibbs energy | 2 |

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the Ca–Fe–O system (61)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 1505 | other: L + F + WF -> C4WF8 |  | model | [1] Hillert 1990 | Table IV, p. 12, row 49; `ORC-TUVE3MQEQ2` |  |
| 1503 | other: L + F + WF -> C4WF8 |  | experimental | [1] Hillert 1990; _cites Phillips 1960_ | Table IV, p. 12, row 48; `ORC-2THY6VCBRM` |  |
| 1493 | other: L + F -> CF2 + C4WF8 |  | experimental | [1] Hillert 1990; _cites Phillips 1960_ | Table IV, p. 12, row 46; `ORC-JOOS6R57SO` |  |
| 1485 | other: L -> WF + C2F + C4WF4 |  | experimental | [1] Hillert 1990; _cites Phillips 1960_ | Table IV, p. 12, row 44; `ORC-2WOCZPOYWZ` |  |
| 1484 | other: L + F -> CF2 + C4WF8 |  | model | [1] Hillert 1990 | Table IV, p. 12, row 47; `ORC-T44TQ5JPNY` |  |
| 1483 | other: L + C2F -> CF + C4WF4 |  | experimental | [1] Hillert 1990; _cites Phillips 1960_ | Table IV, p. 12, row 42; `ORC-GTUXSLG3NT` |  |
| 1475 | other: L -> WF + C2F + C4WF4 |  | model | [1] Hillert 1990 | Table IV, p. 12, row 45; `ORC-TRJHGFHP6H` |  |
| 1473 | other: L + CF2 -> CF + C4WF8 |  | experimental | [1] Hillert 1990; _cites Phillips 1960_ | Table IV, p. 12, row 40; `ORC-LFWPCCZPI3` |  |
| 1470 | other: L + C4WF4 -> CF + WF |  | experimental | [1] Hillert 1990; _cites Phillips 1960_ | Table IV, p. 12, row 38; `ORC-KHX2QBKSRG` |  |
| 1470 | other: L + C2F -> CF + C4WF4 |  | model | [1] Hillert 1990 | Table IV, p. 12, row 43; `ORC-YER4YXRJTV` |  |
| 1467 | other: L -> CF + WF + C4WF8 |  | experimental | [1] Hillert 1990; _cites Phillips 1960_ | Table IV, p. 12, row 36; `ORC-62PHDADIFD` |  |
| 1467 | other: L + CF2 -> CF + C4WF8 |  | model | [1] Hillert 1990 | Table IV, p. 12, row 41; `ORC-W4R22VIETP` |  |
| 1463 | other: L + WF + C2F -> CWF |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 34; `ORC-QOAPNLVTAF` |  |
| 1460 | other: L + C4WF4 -> CF + WF |  | model | [1] Hillert 1990 | Table IV, p. 12, row 39; `ORC-UCJ5WJGNYX` |  |
| 1460 | other: L -> CF + WF + C4WF8 |  | model | [1] Hillert 1990 | Table IV, p. 12, row 37; `ORC-XY6QJ7SRP3` |  |
| 1455 | other: L + WF + C2F -> CWF |  | model | [1] Hillert 1990 | Table IV, p. 12, row 35; `ORC-PXYEKESITU` |  |
| 1451 | other: CF2 -> CF + F (+ C4WF8) |  | model | [1] Hillert 1990 | Table IV, p. 12, row 33; `ORC-XFY5XVL4SS` |  |
| 1440 | other: C4WF8 -> F + WF + CF |  | model | [1] Hillert 1990 | Table IV, p. 12, row 32; `ORC-Y26ZBYVYDS` |  |
| 1423 | other: WF + L -> CWF + W |  | model | [1] Hillert 1990 | Table IV, p. 12, row 31; `ORC-UWOF3J5NJ5` |  |
| 1423 | other: WF + L -> CWF + W |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 30; `ORC-ZKYGCHDGBC` |  |
| 1404 | other: L + Fe + C -> W |  | model | [1] Hillert 1990 | Table IV, p. 12, row 29; `ORC-HFBSORKK47` |  |
| 1400 | eutectic: W + CWF + C2F -> CW3F |  | experimental | [1] Hillert 1990; _cites Chung 1988_ | Table IV, p. 12, row 51; `ORC-KGUHQZQZWL` |  |
| 1396 | eutectic: W + CWF + C2F -> CW3F |  | model | [1] Hillert 1990 | Table IV, p. 12, row 53; `ORC-Y3WTX3POBY` |  |
| 1393 | other: L + Fe + C -> W |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 28; `ORC-KDUBDEW3DN` |  |
| 1388 | other: L + C -> W + C2F |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 26; `ORC-DJFPQIRXFZ` |  |
| 1383 | other: L + CWF -> C2F + W |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 60; `ORC-CL6B373U5O` |  |
| 1381 | other: L + C -> W + C2F |  | model | [1] Hillert 1990 | Table IV, p. 12, row 27; `ORC-A7WSE3VNU7` |  |
| 1380 | other: L + W + CWF -> CW3F |  | model | [1] Hillert 1990 | Table IV, p. 12, row 25; `ORC-QNEKAD5A7G` |  |
| 1374 | other: L + CWF -> CW3F + C2F |  | model | [1] Hillert 1990 | Table IV, p. 12, row 23; `ORC-FHGKWKF4HS` |  |
| 1373 | other: L + CWF -> CW3F + C2F |  | experimental | [1] Hillert 1990; _cites Bergman 1989_ [doi](https://doi.org/10.1111/j.1151-2916.1989.tb07653.x) | Table IV, p. 12, row 22; `ORC-5IJUE54VE7` |  |
| 1373 | other: L + W + CWF -> CW3F |  | experimental | [1] Hillert 1990; _cites Bergman 1989_ [doi](https://doi.org/10.1111/j.1151-2916.1989.tb07653.x) | Table IV, p. 12, row 24; `ORC-IIUDSK2LUB` |  |
| 1373 | other: L + CW3F -> C2F + W |  | experimental | [1] Hillert 1990; _cites Bergman 1989_ [doi](https://doi.org/10.1111/j.1151-2916.1989.tb07653.x) | Table IV, p. 12, row 20; `ORC-JEGH3S77UP` |  |
| 1372 | other: L + CWF -> C2F + W |  | model | [1] Hillert 1990 | Table IV, p. 12, row 61; `ORC-ZSYZMHMVF4` |  |
| 1371 | other: L + CW3F -> C2F + W |  | model | [1] Hillert 1990 | Table IV, p. 12, row 21; `ORC-PZXX7D5XVX` |  |
| 1355 | other: WF + CF -> C4WF4 + F |  | model | [1] Hillert 1990 | Table IV, p. 12, row 19; `ORC-6G356AYZFG` |  |
| 1343 | quasi-peritectic: W + C -> C2F + Fe |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 17; `ORC-WCP5GSRWIR` |  |
| 1333 | eutectic: W + CWF + C2F -> CW3F |  | experimental | [1] Hillert 1990; _cites Schiirmann 1973_ | Table IV, p. 12, row 50; `ORC-EZA3DOMNNQ` |  |
| 1333 | quasi-peritectic: W + C -> C2F + Fe |  | experimental | [1] Hillert 1990; _cites Bj 1984_ | Table IV, p. 12, row 16; `ORC-OGI535GSGE` |  |
| 1324 | quasi-peritectic: W + C -> C2F + Fe |  | model | [1] Hillert 1990 | Table IV, p. 12, row 18; `ORC-QVU6GF57RK` |  |
| 1318 | quasi-peritectic: W + C -> C2F + Fe |  | experimental | [1] Hillert 1990; _cites Abbattista 1975_ | Table IV, p. 12, row 15; `ORC-UNWHLFMVZI` |  |
| 1308 | eutectic: W + CWF + C2F -> CW3F |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 52; `ORC-J7X5JOQGLV` |  |
| 1307 | other: WF + C2F -> CWF + C4WF4 |  | model | [1] Hillert 1990 | Table IV, p. 12, row 13; `ORC-MPI333ENFM` |  |
| 1300 | quasi-peritectic: W + C -> C2F + Fe |  | experimental | [1] Hillert 1990; _cites Chung 1988_ | Table IV, p. 12, row 14; `ORC-2IOYGOJMR7` |  |
| 1113 | peritectic: W + C2F -> CW3F + Fe |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 11; `ORC-I32G3NSO62` |  |
| 1095 | peritectic: W + C2F -> CW3F + Fe |  | model | [1] Hillert 1990 | Table IV, p. 12, row 12; `ORC-OFSTC6D3PQ` |  |
| 1088 | peritectic: W + C2F -> CW3F + Fe |  | experimental | [1] Hillert 1990; _cites Chung 1988_ | Table IV, p. 12, row 10; `ORC-MNESFMJ5IB` |  |
| 1019 | other: W + CWF -> CW3F + WF |  | model | [1] Hillert 1990 | Table IV, p. 12, row 9; `ORC-CDTSF4UR7D` |  |
| 953 | other: C2F + CW3F -> CWF + Fe |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 7; `ORC-MXKYW32C2Y` |  |
| 935 | other: C2F + CW3F -> CWF + Fe |  | experimental | [1] Hillert 1990; _cites Chung 1988_ | Table IV, p. 12, row 6; `ORC-ERUHUFQPKI` |  |
| 925 | other: C2F + CW3F -> CWF + Fe |  | model | [1] Hillert 1990 | Table IV, p. 12, row 8; `ORC-5SL7PN6S3W` |  |
| 918 | other: CW3F -> Fe + W + CWF |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 54; `ORC-NQEEYTCWHR` |  |
| 878 | other: C2F + CWF -> C4WF4 + Fe |  | model | [1] Hillert 1990 | Table IV, p. 12, row 5; `ORC-XG42546DCN` |  |
| 855 | other: CWF -> CW3F + C4WF4 (+ WF) |  | model | [1] Hillert 1990 | Table IV, p. 12, row 3; `ORC-CCGHHSPSC4` |  |
| 855 | other: CWF -> CW3F + C4WF4 (+ Fe) |  | model | [1] Hillert 1990 | Table IV, p. 12, row 4; `ORC-PCGZKOI2K7` |  |
| 843 | other: W -> Fe + WF + CWF |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 56; `ORC-5LG5O4ARNH` |  |
| 827 | other: W -> Fe + WF + CW3F |  | model | [1] Hillert 1990 | Table IV, p. 12, row 2; `ORC-S2EKXQ4R5U` |  |
| 827 | other: W -> Fe + WF + CWF |  | model | [1] Hillert 1990 | Table IV, p. 12, row 57; `ORC-UIEKY5Q6B2` |  |
| 826 | other: CW3F -> Fe + WF + C4WF4 |  | model | [1] Hillert 1990 | Table IV, p. 12, row 1; `ORC-HPPJI4E2KL` |  |
| 787 | other: CW3F -> Fe + W + CWF |  | model | [1] Hillert 1990 | Table IV, p. 12, row 55; `ORC-MVBPMSUKK7` |  |
| 773 | other: CWF -> Fe + WF + C2F |  | experimental | [1] Hillert 1990; _cites Turkdogan 1961_ | Table IV, p. 12, row 58; `ORC-LXHD4BEZUT` |  |
| 688 | other: CWF -> Fe + WF + C2F |  | model | [1] Hillert 1990 | Table IV, p. 12, row 59; `ORC-TJQ2R2YEYQ` |  |

## Other properties

### Phase transition (1)

Table: Phase transition, Ca–Fe–O system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase transition | 1380 K | 1380 | CW3F + CWF + liquid | model | [1] Hillert 1990 | p. 7; `ORC-EU4I2QJDVN` | “The present assessment comes close to the latter results and predicts that CW3F is stable up to 1380 K, where it decomposes to wiistite, CWF, and liquid.” |

### Heat capacity / entropy / enthalpy (8)

Table: Heat capacity / entropy / enthalpy, Ca–Fe–O system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Entropy; _printed: S (298.15)_ | 188.7 J/mol (basis unstated)/K | 298.15 | C2F | experimental | [1] Hillert 1990; _cites King 1954_ [doi](https://doi.org/10.1021/ja01651a092) | Table I, p. 5, row 4; `ORC-JXE5JW2MGS.4bfe28` |  |
| Entropy; _printed: S (298.15)_ | 189.4 J/mol (basis unstated)/K | 298.15 | C2F | model | [1] Hillert 1990 | Table I, p. 5, row 3; `ORC-KLV6GW2RH6.e5ec9d` |  |
| Entropy; _printed: S (298.15)_ | 145.2 J/mol (basis unstated)/K | 298.15 | CF | experimental | [1] Hillert 1990; _cites King 1954_ [doi](https://doi.org/10.1021/ja01651a092) | Table I, p. 5, row 2; `ORC-J6CM5ETDOG.106a38` |  |
| Entropy; _printed: S (298.15)_ | 145.9 J/mol (basis unstated)/K | 298.15 | CF | model | [1] Hillert 1990 | Table I, p. 5, row 1; `ORC-TLXEP6FAYF.055253` |  |
| Heat capacity; _printed: Cp (298.15)_ | 192.9 J/mol (basis unstated)/K | 298.15 | C2F | experimental | [1] Hillert 1990; _cites King 1954_ [doi](https://doi.org/10.1021/ja01651a092) | Table I, p. 5, row 4; `ORC-JXE5JW2MGS.65ec65` |  |
| Heat capacity; _printed: Cp (298.15)_ | 197 J/mol (basis unstated)/K | 298.15 | C2F | model | [1] Hillert 1990 | Table I, p. 5, row 3; `ORC-KLV6GW2RH6.7d7f11` |  |
| Heat capacity; _printed: Cp (298.15)_ | 153.6 J/mol (basis unstated)/K | 298.15 | CF | experimental | [1] Hillert 1990; _cites King 1954_ [doi](https://doi.org/10.1021/ja01651a092) | Table I, p. 5, row 2; `ORC-J6CM5ETDOG.74ba31` |  |
| Heat capacity; _printed: Cp (298.15)_ | 155.3 J/mol (basis unstated)/K | 298.15 | CF | model | [1] Hillert 1990 | Table I, p. 5, row 1; `ORC-TLXEP6FAYF.f9515b` |  |

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

Table: Activity / EMF / Gibbs energy, Ca–Fe–O system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Chemical potential; _printed: oxygen potential_ | -112.5 kcal/mole O2 | 563.15 | CWF + Fe + WF + C2F | model | [1] Hillert 1990 | p. 9; `ORC-NYBSSYALLF` | “Reeve and Gregory12sl gave a more careful consideration of the position of the univariant line X and predicted that it would intersect the other lines to form the invariant equilibrium VII at 290 ~ and -112.5 kcal/ mole 02.” |
| Chemical potential; _printed: oxygen potential_ | -105.6 kcal/mole O2 | 688.15 | WF | model | [1] Hillert 1990 | p. 9; `ORC-TUKJM5VKEW` | “If we extend the X line below point XIX, we find that the present assessment predicts that the metastable equilibrium VII should occur at 415 ~ and -105.6 kcal/mole 02.” |

## Sources

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

1. Mats Hillert, Malin Selleby, Bo Sundman, An assessment of the Ca-Fe-O system, Metall Trans A 21, 2759-2776 (1990). [doi:10.1007/bf02646071](https://doi.org/10.1007/bf02646071)

## 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 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); 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).

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_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/).